Method and apparatus of broadcast signals and channels for system information transmission

ABSTRACT

A method for receiving a broadcasting signal in a wireless communication system. The method comprises receiving, from a base station (BS), a physical broadcasting channel (PBCH) content over a PBCH, and determining the PBCH content including a payload, wherein the payload includes uncommon information within a transmission time interval (TTI) of the PBCH that comprises at least a portion of a 10-bit system frame number (SFN), a half frame index within a radio frame, and at least part of a synchronization signal (SS) block time index.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/823,310, filed Nov. 27, 2017, which claims priority to U.S.Provisional Patent Application No. 62/432,379, filed Dec. 9, 2016; U.S.Provisional Patent Application No. 62/435,516, filed Dec. 16, 2016; U.S.Provisional Patent Application No. 62/438,064, filed Dec. 22, 2016; U.S.Provisional Patent Application No. 62/443,999, filed Jan. 9, 2017; U.S.Provisional Patent Application No. 62/454,386, filed Feb. 3, 2017; U.S.Provisional Patent Application No. 62/475,488, filed Mar. 23, 2017; U.S.Provisional Patent Application No. 62/483,010, filed Apr. 7, 2017; U.S.Provisional Patent Application No. 62/511,909, filed May 26, 2017; U.S.Provisional Patent Application No. 62/521,876, filed Jun. 19, 2017; andU.S. Provisional Patent Application No. 62/541,400, filed Aug. 4, 2017.The contents of the above-identified patent documents are incorporatedherein by reference.

TECHNICAL FIELD

The present application relates generally to broadcast signals andchannel. More specifically, this disclosure relates to systeminformation transmission in an advanced wireless communication system.

BACKGROUND

In a wireless communication network, a network access and a radioresource management (RRM) are enabled by physical layer synchronizationsignals and higher (MAC) layer procedures. In particular, a UE attemptsto detect the presence of synchronization signals along with at leastone cell identification (ID) for initial access. Once the UE is in thenetwork and associated with a serving cell, the UE monitors severalneighboring cells by attempting to detect their synchronization signalsand/or measuring the associated cell-specific reference signals (RSs).For next generation cellular systems such as third generationpartnership-new radio access or interface (3GPP-NR), efficient andunified radio resource acquisition or tracking mechanism which works forvarious use cases such as enhanced mobile broadband (eMBB), ultrareliable low latency (URLLC), massive machine type communication (mMTC),each corresponding to a different coverage requirement and frequencybands with different propagation losses is desirable. Most likelydesigned with a different network and radio resource paradigm, seamlessand low-latency RRM is also desirable.

SUMMARY

Embodiments of the present disclosure provide a synchronization signaldesign in an advanced wireless communication system.

In one embodiment, a user equipment (UE) for receiving a broadcastingsignal in a wireless communication system is provided. The UE comprisesa transceiver configured to receive, from a base station (BS), aphysical broadcasting channel (PBCH) content over a PBCH. The UE furthercomprises at least one processor configured to determine the PBCHcontent including a payload, wherein the payload includes uncommoninformation within a transmission time interval (TTI) of the PBCH thatcomprises at least a portion of a 10-bit system frame number (SFN), ahalf frame index within a radio frame, and at least part of asynchronization signal (SS) block time index.

In another embodiment, a base station (BS) for transmitting a broadcastsignal in a wireless communication system is provided. The BS comprisesat least one processor configured to generate a payload includinguncommon information within a transmission time interval (TTI) of aphysical broadcasting channel (PBCH) comprising at least a portion of a10-bit system frame number (SFN), a half frame index within a radioframe, and at least part of a synchronization signal (SS) block timeindex and determine a PBCH content including the generated payload. TheBS further comprises a transceiver configured to transmit the PBCHcontent to a user equipment (UE) over a PBCH.

In yet another embodiment, a method for receiving a broadcasting signalin a wireless communication system is provided. The method comprisesreceiving, from a base station (BS), a physical broadcasting channel(PBCH) content over a PBCH and determining the PBCH content including apayload, wherein the payload includes uncommon information within atransmission time interval (TTI) of the PBCH that comprises at least aportion of a 10-bit system frame number (SFN), a half frame index withina radio frame, and at least part of a synchronization signal (SS) blocktime index.

Other technical features may be readily apparent to one skilled in theart from the following figures, descriptions, and claims.

Before undertaking the DETAILED DESCRIPTION below, it may beadvantageous to set forth definitions of certain words and phrases usedthroughout this patent document. The term “couple” and its derivativesrefer to any direct or indirect communication between two or moreelements, whether or not those elements are in physical contact with oneanother. The terms “transmit,” “receive,” and “communicate,” as well asderivatives thereof, encompass both direct and indirect communication.The terms “include” and “comprise,” as well as derivatives thereof, meaninclusion without limitation. The term “or” is inclusive, meaningand/or. The phrase “associated with,” as well as derivatives thereof,means to include, be included within, interconnect with, contain, becontained within, connect to or with, couple to or with, be communicablewith, cooperate with, interleave, juxtapose, be proximate to, be boundto or with, have, have a property of, have a relationship to or with, orthe like. The term “controller” means any device, system or part thereofthat controls at least one operation. Such a controller may beimplemented in hardware or a combination of hardware and software and/orfirmware. The functionality associated with any particular controllermay be centralized or distributed, whether locally or remotely. Thephrase “at least one of,” when used with a list of items, means thatdifferent combinations of one or more of the listed items may be used,and only one item in the list may be needed. For example, “at least oneof: A, B, and C” includes any of the following combinations: A, B, C, Aand B, A and C, B and C, and A and B and C.

Moreover, various functions described below can be implemented orsupported by one or more computer programs, each of which is formed fromcomputer readable program code and embodied in a computer readablemedium. The terms “application” and “program” refer to one or morecomputer programs, software components, sets of instructions,procedures, functions, objects, classes, instances, related data, or aportion thereof adapted for implementation in a suitable computerreadable program code. The phrase “computer readable program code”includes any type of computer code, including source code, object code,and executable code. The phrase “computer readable medium” includes anytype of medium capable of being accessed by a computer, such as readonly memory (ROM), random access memory (RAM), a hard disk drive, acompact disc (CD), a digital video disc (DVD), or any other type ofmemory. A “non-transitory” computer readable medium excludes wired,wireless, optical, or other communication links that transporttransitory electrical or other signals. A non-transitory computerreadable medium includes media where data can be permanently stored andmedia where data can be stored and later overwritten, such as arewritable optical disc or an erasable memory device.

Definitions for other certain words and phrases are provided throughoutthis patent document. Those of ordinary skill in the art shouldunderstand that in many if not most instances, such definitions apply toprior as well as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsadvantages, reference is now made to the following description taken inconjunction with the accompanying drawings, in which like referencenumerals represent like parts:

FIG. 1 illustrates an example wireless network according to embodimentsof the present disclosure;

FIG. 2 illustrates an example eNB according to embodiments of thepresent disclosure;

FIG. 3 illustrates an example UE according to embodiments of the presentdisclosure;

FIG. 4A illustrates a high-level diagram of an orthogonal frequencydivision multiple access transmit path according to embodiments of thepresent disclosure;

FIG. 4B illustrates a high-level diagram of an orthogonal frequencydivision multiple access receive path according to embodiments of thepresent disclosure;

FIG. 5 illustrates a transmitter block diagram for a PDSCH in a subframeaccording to embodiments of the present disclosure;

FIG. 6 illustrates a receiver block diagram for a PDSCH in a subframeaccording to embodiments of the present disclosure;

FIG. 7 illustrates a transmitter block diagram for a PUSCH in a subframeaccording to embodiments of the present disclosure;

FIG. 8 illustrates a receiver block diagram for a PUSCH in a subframeaccording to embodiments of the present disclosure;

FIG. 9 illustrates an example multiplexing of two slices according toembodiments of the present disclosure;

FIG. 10 illustrates an example antenna blocks according to embodimentsof the present disclosure;

FIG. 11 illustrates an example UE mobility scenario according toembodiments of the present disclosure;

FIG. 12 illustrates an example beam sweeping operation according toembodiments of the present disclosure;

FIG. 13 illustrates an example PSS/SSS/PBCH in long-term evolutionsystem according to embodiments of the present disclosure;

FIG. 14A illustrates an example TDM based NR-SSS and NRPBCH-transmission according to embodiments of the present disclosure;

FIGS. 14B and 14C illustrate examples IFDM based NR-SSS and NR-PBCHtransmissions according to embodiments of the present disclosure;

FIGS. 14D and 14E illustrate examples block IFDM based NR-SSS andNR-PBCH transmissions according to embodiments of the presentdisclosure;

FIGS. 14F and 14G illustrate examples combination ofNR-PSS/NR-SSS/NR-PBCH transmissions according to embodiments of thepresent disclosure;

FIG. 15 illustrates an example beam transmission according toembodiments of the present disclosure;

FIG. 16 illustrates an example essential bit information according toembodiments of the present disclosure;

FIG. 17 illustrates a flow chart of a method for NR-PBCH constructionaccording to embodiments of the present disclosure;

FIG. 18 illustrates an example frame structure according to embodimentsof the present disclosure;

FIG. 19 illustrates an example RE for common and uncommon informationaccording to embodiments of the present disclosure;

FIGS. 20A and 20B illustrate examples multiplexing patterns according toembodiments of the present disclosure;

FIG. 21 illustrates an example two codewords for PBCH coding accordingto embodiments of the present disclosure;

FIG. 22 illustrates an example one codeword for PBCH coding according toembodiments of the present disclosure;

FIG. 23 illustrates an example PRACH format according to embodiments ofthe present disclosure;

FIG. 24 illustrates another example PRACH format according toembodiments of the present disclosure;

FIG. 25 illustrates yet another example PRACH format according toembodiments of the present disclosure; and

FIG. 26 illustrates yet another example PRACH format according toembodiments of the present disclosure.

DETAILED DESCRIPTION

FIG. 1 through FIG. 26, discussed below, and the various embodimentsused to describe the principles of the present disclosure in this patentdocument are by way of illustration only and should not be construed inany way to limit the scope of the disclosure. Those skilled in the artwill understand that the principles of the present disclosure may beimplemented in any suitably arranged system or device.

The following documents and standards descriptions are herebyincorporated by reference into the present disclosure as if fully setforth herein: 3GPP TS 36.211 v13.2.0, “E-UTRA, Physical channels andmodulation;” 3GPP TS 36.212 v13.2.0, “E-UTRA, Multiplexing and Channelcoding;” 3GPP TS 36.213 v13.2.0, “E-UTRA, Physical Layer Procedures;”3GPP TS 36.321 v13.2.0, “E-UTRA, Medium Access Control (MAC) protocolspecification;” and 3GPP TS 36.331 v13.2.0, “E-UTRA, Radio ResourceControl (RRC) protocol specification.”

To meet the demand for wireless data traffic having increased sincedeployment of 4G communication systems, efforts have been made todevelop an improved 5G or pre-5G communication system. Therefore, the 5Gor pre-5G communication system is also called a “beyond 4G network” or a“post LTE system.”

The 5G communication system is considered to be implemented in higherfrequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higherdata rates. To decrease propagation loss of the radio waves and increasethe transmission coverage, the beamforming, massive multiple-inputmultiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna,an analog beam forming, large scale antenna techniques and the like arediscussed in 5G communication systems.

In addition, in 5G communication systems, development for system networkimprovement is under way based on advanced small cells, cloud radioaccess networks (RANs), ultra-dense networks, device-to-device (D2D)communication, wireless backhaul communication, moving network,cooperative communication, coordinated multi-points (CoMP) transmissionand reception, interference mitigation and cancellation and the like.

In the 5G system, hybrid frequency shift keying and quadrature amplitudemodulation (FQAM) and sliding window superposition coding (SWSC) as anadaptive modulation and coding (AMC) technique, and filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse codemultiple access (SCMA) as an advanced access technology have beendeveloped.

FIGS. 1-4B below describe various embodiments implemented in wirelesscommunications systems and with the use of orthogonal frequency divisionmultiplexing (OFDM) or orthogonal frequency division multiple access(OFDMA) communication techniques. The descriptions of FIGS. 1-3 are notmeant to imply physical or architectural limitations to the manner inwhich different embodiments may be implemented. Different embodiments ofthe present disclosure may be implemented in any suitably-arrangedcommunications system.

FIG. 1 illustrates an example wireless network according to embodimentsof the present disclosure. The embodiment of the wireless network shownin FIG. 1 is for illustration only. Other embodiments of the wirelessnetwork 100 could be used without departing from the scope of thisdisclosure.

As shown in FIG. 1, the wireless network includes an eNB 101, an eNB102, and an eNB 103. The eNB 101 communicates with the eNB 102 and theeNB 103. The eNB 101 also communicates with at least one network 130,such as the Internet, a proprietary Internet Protocol (IP) network, orother data network.

The eNB 102 provides wireless broadband access to the network 130 for afirst plurality of user equipments (UEs) within a coverage area 120 ofthe eNB 102. The first plurality of UEs includes a UE 111, which may belocated in a small business (SB); a UE 112, which may be located in anenterprise (E); a UE 113, which may be located in a WiFi hotspot (HS); aUE 114, which may be located in a first residence (R); a UE 115, whichmay be located in a second residence (R); and a UE 116, which may be amobile device (M), such as a cell phone, a wireless laptop, a wirelessPDA, or the like. The eNB 103 provides wireless broadband access to thenetwork 130 for a second plurality of UEs within a coverage area 125 ofthe eNB 103. The second plurality of UEs includes the UE 115 and the UE116. In some embodiments, one or more of the eNBs 101-103 maycommunicate with each other and with the UEs 111-116 using 5G, LTE,LTE-A, WiMAX, WiFi, or other wireless communication techniques.

Depending on the network type, the term “base station” or “BS” can referto any component (or collection of components) configured to providewireless access to a network, such as transmit point (TP),transmit-receive point (TRP), an enhanced base station (eNodeB or eNB),a 5G base station (gNB), a macrocell, a femtocell, a WiFi access point(AP), or other wirelessly enabled devices. Base stations may providewireless access in accordance with one or more wireless communicationprotocols, e.g., 5G 3GPP new radio interface/access (NR), long termevolution (LTE), LTE advanced (LTE-A), high speed packet access (HSPA),Wi-Fi 802.11a/b/g/n/ac, etc. For the sake of convenience, the terms “BS”and “TRP” are used interchangeably in this patent document to refer tonetwork infrastructure components that provide wireless access to remoteterminals. Also, depending on the network type, the term “userequipment” or “UE” can refer to any component such as “mobile station,”“subscriber station,” “remote terminal,” “wireless terminal,” “receivepoint,” or “user device.” For the sake of convenience, the terms “userequipment” and “UE” are used in this patent document to refer to remotewireless equipment that wirelessly accesses a BS, whether the UE is amobile device (such as a mobile telephone or smartphone) or is normallyconsidered a stationary device (such as a desktop computer or vendingmachine).

Dotted lines show the approximate extents of the coverage areas 120 and125, which are shown as approximately circular for the purposes ofillustration and explanation only. It should be clearly understood thatthe coverage areas associated with eNBs, such as the coverage areas 120and 125, may have other shapes, including irregular shapes, dependingupon the configuration of the eNBs and variations in the radioenvironment associated with natural and man-made obstructions.

As described in more detail below, one or more of the UEs 111-116include circuitry, programing, or a combination thereof, for efficientCSI reporting on PUCCH in an advanced wireless communication system. Incertain embodiments, and one or more of the eNBs 101-103 includescircuitry, programing, or a combination thereof, for receiving efficientCSI reporting on PUCCH in an advanced wireless communication system.

Although FIG. 1 illustrates one example of a wireless network, variouschanges may be made to FIG. 1. For example, the wireless network couldinclude any number of eNBs and any number of UEs in any suitablearrangement. Also, the eNB 101 could communicate directly with anynumber of UEs and provide those UEs with wireless broadband access tothe network 130. Similarly, each eNB 102-103 could communicate directlywith the network 130 and provide UEs with direct wireless broadbandaccess to the network 130. Further, the eNBs 101, 102, and/or 103 couldprovide access to other or additional external networks, such asexternal telephone networks or other types of data networks.

FIG. 2 illustrates an example eNB 102 according to embodiments of thepresent disclosure. The embodiment of the eNB 102 illustrated in FIG. 2is for illustration only, and the eNBs 101 and 103 of FIG. 1 could havethe same or similar configuration. However, eNBs come in a wide varietyof configurations, and FIG. 2 does not limit the scope of thisdisclosure to any particular implementation of an eNB.

As shown in FIG. 2, the eNB 102 includes multiple antennas 205 a-205 n,multiple RF transceivers 210 a-210 n, transmit (TX) processing circuitry215, and receive (RX) processing circuitry 220. The eNB 102 alsoincludes a controller/processor 225, a memory 230, and a backhaul ornetwork interface 235.

The RF transceivers 210 a-210 n receive, from the antennas 205 a-205 n,incoming RF signals, such as signals transmitted by UEs in the network100. The RF transceivers 210 a-210 n down-convert the incoming RFsignals to generate IF or baseband signals. The IF or baseband signalsare sent to the RX processing circuitry 220, which generates processedbaseband signals by filtering, decoding, and/or digitizing the basebandor IF signals. The RX processing circuitry 220 transmits the processedbaseband signals to the controller/processor 225 for further processing.

In some embodiments, the RF transceivers 210 a-210 n are capable oftransmitting the PBCH content to a user equipment (UE) over a PBCH andthe PBCH content using a transmission scheme based on a single antennaport. In such embodiments, the single antenna port used for PBCH contenttransmission is the same as the single antenna port used for a secondarysynchronization signal (SSS) transmission.

In some embodiments, the RF transceivers 210 a-210 n are capable oftransmitting, to a UE, an RMSI content including at least one ofconfiguration information or part of the configuration information forTRS over a physical downlink shared channel (PDSCH) and receiving, fromthe UE, the PRACH preamble based on the PRACH information.

The TX processing circuitry 215 receives analog or digital data (such asvoice data, web data, e-mail, or interactive video game data) from thecontroller/processor 225. The TX processing circuitry 215 encodes,multiplexes, and/or digitizes the outgoing baseband data to generateprocessed baseband or IF signals. The RF transceivers 210 a-210 nreceive the outgoing processed baseband or IF signals from the TXprocessing circuitry 215 and up-converts the baseband or IF signals toRF signals that are transmitted via the antennas 205 a-205 n.

The controller/processor 225 can include one or more processors or otherprocessing devices that control the overall operation of the eNB 102.For example, the controller/processor 225 could control the reception offorward channel signals and the transmission of reverse channel signalsby the RF transceivers 210 a-210 n, the RX processing circuitry 220, andthe TX processing circuitry 215 in accordance with well-knownprinciples. The controller/processor 225 could support additionalfunctions as well, such as more advanced wireless communicationfunctions. For instance, the controller/processor 225 could support beamforming or directional routing operations in which outgoing signals frommultiple antennas 205 a-205 n are weighted differently to effectivelysteer the outgoing signals in a desired direction. Any of a wide varietyof other functions could be supported in the eNB 102 by thecontroller/processor 225.

The controller/processor 225 is also capable of executing programs andother processes resident in the memory 230, such as an OS. Thecontroller/processor 225 can move data into or out of the memory 230 asrequired by an executing process.

The controller/processor 225 is also coupled to the backhaul or networkinterface 235. The backhaul or network interface 235 allows the eNB 102to communicate with other devices or systems over a backhaul connectionor over a network. The interface 235 could support communications overany suitable wired or wireless connection(s). For example, when the eNB102 is implemented as part of a cellular communication system (such asone supporting 5G, LTE, or LTE-A), the interface 235 could allow the eNB102 to communicate with other eNBs over a wired or wireless backhaulconnection. When the eNB 102 is implemented as an access point, theinterface 235 could allow the eNB 102 to communicate over a wired orwireless local area network or over a wired or wireless connection to alarger network (such as the Internet). The interface 235 includes anysuitable structure supporting communications over a wired or wirelessconnection, such as an Ethernet or RF transceiver.

In some embodiments, the controller/processor 225 is capable ofgenerating a payload including uncommon information within atransmission time interval (TTI) of a physical broadcasting channel(PBCH) comprising at least a portion of a 10-bit system frame number(SFN), a half frame index within a radio frame, and at least part of asynchronization signal (SS) block time index and determining a PBCHcontent including the generated payload.

In some embodiments, the controller/processor 225 is capable ofdetermining configuration information for a remaining minimum systeminformation (RMSI) transmission, the configuration information includingat least one of frequency resource configuration information or timeresource configuration information for a control resource set (CORESET)for the RMSI transmission and generating the payload including theconfiguration information.

In some embodiments, the controller/processor 225 is capable ofgenerating the payload including at least one of configurationinformation or part of the configuration information for a trackingreference signal (TRS), the configuration information including at leastone of a number of antenna ports, a periodicity, or a timing offset, anddetermining an RMSI content including the generated payload.

In some embodiments, the controller/processor 225 is capable ofgenerating physical random access channel (PRACH) information includinga format of a PRACH preamble, wherein the format of the PRACH preambleincludes at least one of a preamble sequence length or a numerology.

The memory 230 is coupled to the controller/processor 225. Part of thememory 230 could include a RAM, and another part of the memory 230 couldinclude a Flash memory or other ROM.

Although FIG. 2 illustrates one example of eNB 102, various changes maybe made to FIG. 2. For example, the eNB 102 could include any number ofeach component shown in FIG. 2. As a particular example, an access pointcould include a number of interfaces 235, and the controller/processor225 could support routing functions to route data between differentnetwork addresses. As another particular example, while shown asincluding a single instance of TX processing circuitry 215 and a singleinstance of RX processing circuitry 220, the eNB 102 could includemultiple instances of each (such as one per RF transceiver). Also,various components in FIG. 2 could be combined, further subdivided, oromitted and additional components could be added according to particularneeds.

FIG. 3 illustrates an example UE 116 according to embodiments of thepresent disclosure. The embodiment of the UE 116 illustrated in FIG. 3is for illustration only, and the UEs 111-115 of FIG. 1 could have thesame or similar configuration. However, UEs come in a wide variety ofconfigurations, and FIG. 3 does not limit the scope of this disclosureto any particular implementation of a UE.

As shown in FIG. 3, the UE 116 includes an antenna 305, a radiofrequency (RF) transceiver 310, TX processing circuitry 315, amicrophone 320, and receive (RX) processing circuitry 325. The UE 116also includes a speaker 330, a processor 340, an input/output (I/O)interface (IF) 345, a touchscreen 350, a display 355, and a memory 360.The memory 360 includes an operating system (OS) 361 and one or moreapplications 362.

The RF transceiver 310 receives, from the antenna 305, an incoming RFsignal transmitted by an eNB of the network 100. The RF transceiver 310down-converts the incoming RF signal to generate an intermediatefrequency (IF) or baseband signal. The IF or baseband signal is sent tothe RX processing circuitry 325, which generates a processed basebandsignal by filtering, decoding, and/or digitizing the baseband or IFsignal. The RX processing circuitry 325 transmits the processed basebandsignal to the speaker 330 (such as for voice data) or to the processor340 for further processing (such as for web browsing data).

In some embodiments, the RF transceiver 310 is capable of receiving,from a base station (BS), a physical broadcasting channel (PBCH) contentover a PBCH and the PBCH content using a transmission scheme based on asingle antenna port, and wherein the single antenna port used for PBCHcontent transmission is the same as the single antenna port used for asecondary synchronization signal (SSS) transmission.

In some embodiments, the RF transceiver 310 is capable of receiving,from the BS, an RMSI content including at least one of configurationinformation or part of the configuration information for TRS over aphysical downlink shared channel (PDSCH) and transmitting, to the BS,the PRACH preamble based on the PRACH information.

The TX processing circuitry 315 receives analog or digital voice datafrom the microphone 320 or other outgoing baseband data (such as webdata, e-mail, or interactive video game data) from the processor 340.The TX processing circuitry 315 encodes, multiplexes, and/or digitizesthe outgoing baseband data to generate a processed baseband or IFsignal. The RF transceiver 310 receives the outgoing processed basebandor IF signal from the TX processing circuitry 315 and up-converts thebaseband or IF signal to an RF signal that is transmitted via theantenna 305.

The processor 340 can include one or more processors or other processingdevices and execute the OS 361 stored in the memory 360 in order tocontrol the overall operation of the UE 116. For example, the processor340 could control the reception of forward channel signals and thetransmission of reverse channel signals by the RF transceiver 310, theRX processing circuitry 325, and the TX processing circuitry 315 inaccordance with well-known principles. In some embodiments, theprocessor 340 includes at least one microprocessor or microcontroller.

The processor 340 is also capable of executing other processes andprograms resident in the memory 360, such as processes for CSI reportingon PUCCH. The processor 340 can move data into or out of the memory 360as required by an executing process. In some embodiments, the processor340 is configured to execute the applications 362 based on the OS 361 orin response to signals received from eNBs or an operator. The processor340 is also coupled to the I/O interface 345, which provides the UE 116with the ability to connect to other devices, such as laptop computersand handheld computers. The I/O interface 345 is the communication pathbetween these accessories and the processor 340.

The processor 340 is also coupled to the touchscreen 350 and the display355. The operator of the UE 116 can use the touchscreen 350 to enterdata into the UE 116. The display 355 may be a liquid crystal display,light emitting diode display, or other display capable of rendering textand/or at least limited graphics, such as from web sites.

In some embodiments, the processor 340 is capable of determining thePBCH content including a payload, wherein the payload includes uncommoninformation within a transmission time interval (TTI) of the PBCH thatcomprises at least a portion of a 10-bit system frame number (SFN), ahalf frame index within a radio frame, and at least part of asynchronization signal (SS) block time index.

In some embodiments, the processor 340 is capable of determining thepayload including configuration information for a remaining minimumsystem information (RMSI) transmission, the configuration informationincluding at least one of frequency resource configuration informationor time resource configuration information for a control resource set(CORESET) for the RMSI transmission, and determining an RMSI contentincluding the payload that comprises at least one of configurationinformation or part of the configuration information for a trackingreference signal (TRS), the configuration information including at leastone of a number of antenna ports, a periodicity, or a timing offset.

In some embodiments, the processor 340 is capable of determiningphysical random access channel (PRACH) information including a format ofa PRACH preamble, wherein the format of the PRACH preamble includes atleast one of a preamble sequence length or a numerology.

The memory 360 is coupled to the processor 340. Part of the memory 360could include a random access memory (RAM), and another part of thememory 360 could include a Flash memory or other read-only memory (ROM).

Although FIG. 3 illustrates one example of UE 116, various changes maybe made to FIG. 3. For example, various components in FIG. 3 could becombined, further subdivided, or omitted and additional components couldbe added according to particular needs. As a particular example, theprocessor 340 could be divided into multiple processors, such as one ormore central processing units (CPUs) and one or more graphics processingunits (GPUs). Also, while FIG. 3 illustrates the UE 116 configured as amobile telephone or smartphone, UEs could be configured to operate asother types of mobile or stationary devices.

FIG. 4A is a high-level diagram of transmit path circuitry. For example,the transmit path circuitry may be used for an orthogonal frequencydivision multiple access (OFDMA) communication. FIG. 4B is a high-leveldiagram of receive path circuitry. For example, the receive pathcircuitry may be used for an orthogonal frequency division multipleaccess (OFDMA) communication. In FIGS. 4A and 4B, for downlinkcommunication, the transmit path circuitry may be implemented in a basestation (eNB) 102 or a relay station, and the receive path circuitry maybe implemented in a user equipment (e.g. user equipment 116 of FIG. 1).In other examples, for uplink communication, the receive path circuitry450 may be implemented in a base station (e.g. eNB 102 of FIG. 1) or arelay station, and the transmit path circuitry may be implemented in auser equipment (e.g. user equipment 116 of FIG. 1).

Transmit path circuitry comprises channel coding and modulation block405, serial-to-parallel (S-to-P) block 410, Size N Inverse Fast FourierTransform (IFFT) block 415, parallel-to-serial (P-to-S) block 420, addcyclic prefix block 425, and up-converter (UC) 430. Receive pathcircuitry 450 comprises down-converter (DC) 455, remove cyclic prefixblock 460, serial-to-parallel (S-to-P) block 465, Size N Fast FourierTransform (FFT) block 470, parallel-to-serial (P-to-S) block 475, andchannel decoding and demodulation block 480.

At least some of the components in FIGS. 4A 400 and 4B 450 may beimplemented in software, while other components may be implemented byconfigurable hardware or a mixture of software and configurablehardware. In particular, it is noted that the FFT blocks and the IFFTblocks described in this disclosure document may be implemented asconfigurable software algorithms, where the value of Size N may bemodified according to the implementation.

Furthermore, although this disclosure is directed to an embodiment thatimplements the Fast Fourier Transform and the Inverse Fast FourierTransform, this is by way of illustration only and may not be construedto limit the scope of the disclosure. It may be appreciated that in analternate embodiment of the present disclosure, the Fast FourierTransform functions and the Inverse Fast Fourier Transform functions mayeasily be replaced by discrete Fourier transform (DFT) functions andinverse discrete Fourier transform (IDFT) functions, respectively. Itmay be appreciated that for DFT and IDFT functions, the value of the Nvariable may be any integer number (i.e., 1, 4, 3, 4, etc.), while forFFT and IFFT functions, the value of the N variable may be any integernumber that is a power of two (i.e., 1, 2, 4, 8, 16, etc.).

In transmit path circuitry 400, channel coding and modulation block 405receives a set of information bits, applies coding (e.g., LDPC coding)and modulates (e.g., quadrature phase shift keying (QPSK) or quadratureamplitude modulation (QAM)) the input bits to produce a sequence offrequency-domain modulation symbols. Serial-to-parallel block 410converts (i.e., de-multiplexes) the serial modulated symbols to paralleldata to produce N parallel symbol streams where N is the IFFT/FFT sizeused in BS 102 and UE 116. Size N IFFT block 415 then performs an IFFToperation on the N parallel symbol streams to produce time-domain outputsignals. Parallel-to-serial block 420 converts (i.e., multiplexes) theparallel time-domain output symbols from Size N IFFT block 415 toproduce a serial time-domain signal. Add cyclic prefix block 425 theninserts a cyclic prefix to the time-domain signal. Finally, up-converter430 modulates (i.e., up-converts) the output of add cyclic prefix block425 to RF frequency for transmission via a wireless channel. The signalmay also be filtered at baseband before conversion to RF frequency.

The transmitted RF signal arrives at UE 116 after passing through thewireless channel, and reverse operations to those at eNB 102 areperformed. Down-converter 455 down-converts the received signal tobaseband frequency, and remove cyclic prefix block 460 removes thecyclic prefix to produce the serial time-domain baseband signal.Serial-to-parallel block 465 converts the time-domain baseband signal toparallel time-domain signals. Size N FFT block 470 then performs an FFTalgorithm to produce N parallel frequency-domain signals.Parallel-to-serial block 475 converts the parallel frequency-domainsignals to a sequence of modulated data symbols. Channel decoding anddemodulation block 480 demodulates and then decodes the modulatedsymbols to recover the original input data stream.

Each of eNBs 101-103 may implement a transmit path that is analogous totransmitting in the downlink to user equipment 111-116 and may implementa receive path that is analogous to receiving in the uplink from userequipment 111-116. Similarly, each one of user equipment 111-116 mayimplement a transmit path corresponding to the architecture fortransmitting in the uplink to eNBs 101-103 and may implement a receivepath corresponding to the architecture for receiving in the downlinkfrom eNBs 101-103.

5G communication system use cases have been identified and described.Those use cases can be roughly categorized into three different groups.In one example, enhanced mobile broadband (eMBB) is determined to dowith high bits/sec requirement, with less stringent latency andreliability requirements. In another example, ultra reliable and lowlatency (URLL) is determined with less stringent bits/sec requirement.In yet another example, massive machine type communication (mMTC) isdetermined that a number of devices can be as many as 100,000 to 1million per km2, but the reliability/throughput/latency requirementcould be less stringent. This scenario may also involve power efficiencyrequirement as well, in that the battery consumption should be minimizedas possible.

A communication system includes a Downlink (DL) that conveys signalsfrom transmission points such as Base Stations (BSs) or NodeBs to UserEquipments (UEs) and an Uplink (UL) that conveys signals from UEs toreception points such as NodeBs. A UE, also commonly referred to as aterminal or a mobile station, may be fixed or mobile and may be acellular phone, a personal computer device, or an automated device. AneNodeB, which is generally a fixed station, may also be referred to asan access point or other equivalent terminology. For LTE systems, aNodeB is often referred as an eNodeB.

In a communication system, such as LTE system, DL signals can includedata signals conveying information content, control signals conveying DLcontrol information (DCI), and reference signals (RS) that are alsoknown as pilot signals. An eNodeB transmits data information through aphysical DL shared channel (PDSCH). An eNodeB transmits DCI through aphysical DL control channel (PDCCH) or an Enhanced PDCCH (EPDCCH).

An eNodeB transmits acknowledgement information in response to datatransport block (TB) transmission from a UE in a physical hybrid ARQindicator channel (PHICH). An eNodeB transmits one or more of multipletypes of RS including a UE-common RS (CRS), a channel state informationRS (CSI-RS), or a demodulation RS (DMRS). A CRS is transmitted over a DLsystem bandwidth (BW) and can be used by UEs to obtain a channelestimate to demodulate data or control information or to performmeasurements. To reduce CRS overhead, an eNodeB may transmit a CSI-RSwith a smaller density in the time and/or frequency domain than a CRS.DMRS can be transmitted only in the BW of a respective PDSCH or EPDCCHand a UE can use the DMRS to demodulate data or control information in aPDSCH or an EPDCCH, respectively. A transmission time interval for DLchannels is referred to as a subframe and can have, for example,duration of 1 millisecond.

DL signals also include transmission of a logical channel that carriessystem control information. A BCCH is mapped to either a transportchannel referred to as a broadcast channel (BCH) when it conveys amaster information block (MIB) or to a DL shared channel (DL-SCH) whenit conveys a System Information Block (SIB). Most system information isincluded in different SIBs that are transmitted using DL-SCH. A presenceof system information on a DL-SCH in a subframe can be indicated by atransmission of a corresponding PDCCH conveying a codeword with a cyclicredundancy check (CRC) scrambled with special system information RNTI(SI-RNTI). Alternatively, scheduling information for a SIB transmissioncan be provided in an earlier SIB and scheduling information for thefirst SIB (SIB-1) can be provided by the MIB.

DL resource allocation is performed in a unit of subframe and a group ofphysical resource blocks (PRBs). A transmission BW includes frequencyresource units referred to as resource blocks (RBs). Each RB includesN_(sc) ^(RB) sub-carriers, or resource elements (REs), such as 12 REs. Aunit of one RB over one subframe is referred to as a PRB. A UE can beallocated M_(PDSCH) RBs for a total of M_(sc) ^(PDSCH)=M_(PDSCH)·N_(sc)^(RB) REs for the PDSCH transmission BW.

UL signals can include data signals conveying data information, controlsignals conveying UL control information (UCI), and UL RS. UL RSincludes DMRS and Sounding RS (SRS). A UE transmits DMRS only in a BW ofa respective PUSCH or PUCCH. An eNodeB can use a DMRS to demodulate datasignals or UCI signals. A UE transmits SRS to provide an eNodeB with anUL CSI. A UE transmits data information or UCI through a respectivephysical UL shared channel (PUSCH) or a Physical UL control channel(PUCCH). If a UE needs to transmit data information and UCI in a same ULsubframe, it may multiplex both in a PUSCH. UCI includes HybridAutomatic Repeat request acknowledgement (HARQ-ACK) information,indicating correct (ACK) or incorrect (NACK) detection for a data TB ina PDSCH or absence of a PDCCH detection (DTX), scheduling request (SR)indicating whether a UE has data in the UE's buffer, rank indicator(RI), and channel state information (CSI) enabling an eNodeB to performlink adaptation for PDSCH transmissions to a UE. HARQ-ACK information isalso transmitted by a UE in response to a detection of a PDCCH/EPDCCHindicating a release of semi-persistently scheduled PDSCH.

An UL subframe includes two slots. Each slot includes N_(symb) ^(UL)symbols for transmitting data information, UCI, DMRS, or SRS. Afrequency resource unit of an UL system BW is a RB. A UE is allocatedN_(RB) RBs for a total of N_(RB)·N_(sc) ^(RB) REs for a transmission BW.For a PUCCH, N_(RB)=1. A last subframe symbol can be used to multiplexSRS transmissions from one or more UEs. A number of subframe symbolsthat are available for data/UCI/DMRS transmission isN_(symb)=2·(N_(symb) ^(UL)−1)−N_(SRS), where N_(SRS)=1 if a lastsubframe symbol is used to transmit SRS and N_(SRS)=0 otherwise.

FIG. 5 illustrates a transmitter block diagram 500 for a PDSCH in asubframe according to embodiments of the present disclosure. Theembodiment of the transmitter block diagram 500 illustrated in FIG. 5 isfor illustration only. FIG. 5 does not limit the scope of thisdisclosure to any particular implementation of the transmitter blockdiagram 500.

As shown in FIG. 5, information bits 510 are encoded by encoder 520,such as a turbo encoder, and modulated by modulator 530, for exampleusing quadrature phase shift keying (QPSK) modulation. A serial toparallel (S/P) converter 540 generates M modulation symbols that aresubsequently provided to a mapper 550 to be mapped to REs selected by atransmission BW selection unit 555 for an assigned PDSCH transmissionBW, unit 560 applies an Inverse fast Fourier transform (IFFT), theoutput is then serialized by a parallel to serial (P/S) converter 570 tocreate a time domain signal, filtering is applied by filter 580, and asignal transmitted 590. Additional functionalities, such as datascrambling, cyclic prefix insertion, time windowing, interleaving, andothers are well known in the art and are not shown for brevity.

FIG. 6 illustrates a receiver block diagram 600 for a PDSCH in asubframe according to embodiments of the present disclosure. Theembodiment of the diagram 600 illustrated in FIG. 6 is for illustrationonly. FIG. 6 does not limit the scope of this disclosure to anyparticular implementation of the diagram 600.

As shown in FIG. 6, a received signal 610 is filtered by filter 620, REs630 for an assigned reception BW are selected by BW selector 635, unit640 applies a fast Fourier transform (FFT), and an output is serializedby a parallel-to-serial converter 650. Subsequently, a demodulator 660coherently demodulates data symbols by applying a channel estimateobtained from a DMRS or a CRS (not shown), and a decoder 670, such as aturbo decoder, decodes the demodulated data to provide an estimate ofthe information data bits 680. Additional functionalities such astime-windowing, cyclic prefix removal, de-scrambling, channelestimation, and de-interleaving are not shown for brevity.

FIG. 7 illustrates a transmitter block diagram 700 for a PUSCH in asubframe according to embodiments of the present disclosure. Theembodiment of the block diagram 700 illustrated in FIG. 7 is forillustration only. FIG. 7 does not limit the scope of this disclosure toany particular implementation of the block diagram 700.

As shown in FIG. 7, information data bits 710 are encoded by encoder720, such as a turbo encoder, and modulated by modulator 730. A discreteFourier transform (DFT) unit 740 applies a DFT on the modulated databits, REs 750 corresponding to an assigned PUSCH transmission BW areselected by transmission BW selection unit 755, unit 760 applies an IFFTand, after a cyclic prefix insertion (not shown), filtering is appliedby filter 770 and a signal transmitted 780.

FIG. 8 illustrates a receiver block diagram 800 for a PUSCH in asubframe according to embodiments of the present disclosure. Theembodiment of the block diagram 800 illustrated in FIG. 8 is forillustration only. FIG. 8 does not limit the scope of this disclosure toany particular implementation of the block diagram 800.

As shown in FIG. 8, a received signal 810 is filtered by filter 820.Subsequently, after a cyclic prefix is removed (not shown), unit 830applies a FFT, REs 840 corresponding to an assigned PUSCH reception BWare selected by a reception BW selector 845, unit 850 applies an inverseDFT (IDFT), a demodulator 860 coherently demodulates data symbols byapplying a channel estimate obtained from a DMRS (not shown), a decoder870, such as a turbo decoder, decodes the demodulated data to provide anestimate of the information data bits 880.

In next generation cellular systems, various use cases are envisionedbeyond the capabilities of LTE system. Termed 5G or the fifth generationcellular system, a system capable of operating at sub-6 GHz and above-6GHz (for example, in mmWave regime) becomes one of the requirements. In3GPP TR 22.891, 74 5G use cases has been identified and described; thoseuse cases can be roughly categorized into three different groups. Afirst group is termed ‘enhanced mobile broadband’ (eMBB), targeted tohigh data rate services with less stringent latency and reliabilityrequirements. A second group is termed “ultra-reliable and low latency(URLL)” targeted for applications with less stringent data raterequirements, but less tolerant to latency. A third group is termed“massive MTC (mMTC)” targeted for large number of low-power deviceconnections such as 1 million per km² with less stringent thereliability, data rate, and latency requirements.

In order for the 5G network to support such diverse services withdifferent quality of services (QoS), one method has been identified inLTE specification, called network slicing. To utilize PHY resourcesefficiently and multiplex various slices (with different resourceallocation schemes, numerologies, and scheduling strategies) in DL-SCH,a flexible and self-contained frame or subframe design is utilized.

FIG. 9 illustrates an example multiplexing of two slices 900 accordingto embodiments of the present disclosure. The embodiment of themultiplexing of two slices 900 illustrated in FIG. 9 is for illustrationonly. FIG. 9 does not limit the scope of this disclosure to anyparticular implementation of the multiplexing of two slices 900.

Two exemplary instances of multiplexing two slices within a commonsubframe or frame are depicted in FIG. 9. In these exemplaryembodiments, a slice can be composed of one or two transmissioninstances where one transmission instance includes a control (CTRL)component (e.g., 920 a, 960 a, 960 b, 920 b, or 960 c) and a datacomponent (e.g., 930 a, 970 a, 970 b, 930 b, or 970 c). In embodiment910, the two slices are multiplexed in frequency domain whereas inembodiment 950, the two slices are multiplexed in time domain. These twoslices can be transmitted with different sets of numerology.

LTE specification supports up to 32 CSI-RS antenna ports which enable aneNB to be equipped with a large number of antenna elements (such as 64or 128). In this case, a plurality of antenna elements is mapped ontoone CSI-RS port. For next generation cellular systems such as 5G, themaximum number of CSI-RS ports can either remain the same or increase.

FIG. 10 illustrates an example antenna blocks 1000 according toembodiments of the present disclosure. The embodiment of the antennablocks 1000 illustrated in FIG. 10 is for illustration only. FIG. 10does not limit the scope of this disclosure to any particularimplementation of the antenna blocks 1000.

For mmWave bands, although the number of antenna elements can be largerfor a given form factor, the number of CSI-RS ports—which can correspondto the number of digitally precoded ports—tends to be limited due tohardware constraints (such as the feasibility to install a large numberof ADCs/DACs at mmWave frequencies) as illustrated in FIG. 10. In thiscase, one CSI-RS port is mapped onto a large number of antenna elementswhich can be controlled by a bank of analog phase shifters. One CSI-RSport can then correspond to one sub-array which produces a narrow analogbeam through analog beamforming. This analog beam can be configured tosweep across a wider range of angles by varying the phase shifter bankacross symbols or subframes. The number of sub-arrays (equal to thenumber of RF chains) is the same as the number of CSI-RS portsN_(CSI-PORT). A digital beamforming unit performs a linear combinationacross N_(CSI-PORT) analog beams to further increase precoding gain.While analog beams are wideband (hence not frequency-selective), digitalprecoding can be varied across frequency sub-bands or resource blocks.

In a 3GPP LTE communication system, network access and radio resourcemanagement (RRM) are enabled by physical layer synchronization signalsand higher (MAC) layer procedures. In particular, a UE attempts todetect the presence of synchronization signals along with at least onecell ID for initial access. Once the UE is in the network and associatedwith a serving cell, the UE monitors several neighboring cells byattempting to detect their synchronization signals and/or measuring theassociated cell-specific RSs (for instance, by measuring their RSRPs).For next generation cellular systems such as 3GPP NR (new radio accessor interface), efficient and unified radio resource acquisition ortracking mechanism which works for various use cases (such as eMBB,URLLC, mMTC, each corresponding to a different coverage requirement) andfrequency bands (with different propagation losses) is desirable. Mostlikely designed with a different network and radio resource paradigm,seamless and low-latency RRM is also desirable. Such goals pose at leastthe following problems in designing an access, radio resource, andmobility management framework.

First, since NR is likely to support even more diversified networktopology, the notion of cell can be redefined or replaced with anotherradio resource entity. As an example, for synchronous networks, one cellcan be associated with a plurality of TRPs (transmit-receive points)similar to a COMP (coordinated multipoint transmission) scenario in LTEspecification. In this case, seamless mobility is a desirable feature.

Second, when large antenna arrays and beamforming are utilized, definingradio resource in terms of beams (although possibly termed differently)can be a natural approach. Given that numerous beamforming architecturescan be utilized, an access, radio resource, and mobility managementframework which accommodates various beamforming architectures (or,instead, agnostic to beamforming architecture) is desirable.

FIG. 11 illustrates an example UE mobility scenario 1100 according toembodiments of the present disclosure. The embodiment of the UE mobilityscenario 1100 illustrated in FIG. 11 is for illustration only. FIG. 11does not limit the scope of this disclosure to any particularimplementation of the UE mobility scenario 1100.

For instance, the framework may be applicable for or agnostic to whetherone beam is formed for one CSI-RS port (for instance, where a pluralityof analog ports are connected to one digital port, and a plurality ofwidely separated digital ports are utilized) or one beam is formed by aplurality of CSI-RS ports. In addition, the framework may be applicablewhether beam sweeping (as illustrated in FIG. 11) is used or not.

Third, different frequency bands and use cases impose different coveragelimitations. For example, mmWave bands impose large propagation losses.Therefore, some form of coverage enhancement scheme is needed. Severalcandidates include beam sweeping (as shown in FIG. 10), repetition,diversity, and/or multi-TRP transmission. For mMTC where transmissionbandwidth is small, time-domain repetition is needed to ensuresufficient coverage.

A UE-centric access which utilizes two levels of radio resource entityis described in FIG. 11. These two levels can be termed as “cell” and“beam”. These two terms are exemplary and used for illustrativepurposes. Other terms such as radio resource (RR) 1 and 2 can also beused. Additionally, the term “beam” as a radio resource unit is to bedifferentiated with, for instance, an analog beam used for beam sweepingin FIG. 10.

As shown in FIG. 11, the first RR level (termed “cell”) applies when aUE enters a network and therefore is engaged in an initial accessprocedure. In 1110, a UE 1111 is connected to cell 1112 after performingan initial access procedure which includes detecting the presence ofsynchronization signals. Synchronization signals can be used for coarsetiming and frequency acquisitions as well as detecting the cellidentification (cell ID) associated with the serving cell. In this firstlevel, the UE observes cell boundaries as different cells can beassociated with different cell IDs. In FIG. 11, one cell is associatedwith one TRP (in general, one cell can be associated with a plurality ofTRPs). Since cell ID is a MAC layer entity, initial access involves notonly physical layer procedure(s) (such as cell search viasynchronization signal acquisition) but also MAC layer procedure(s).

The second RR level (termed “beam”) applies when a UE is alreadyconnected to a cell and hence in the network. In this second level, a UE1111 can move within the network without observing cell boundaries asillustrated in embodiment 1150. That is, UE mobility is handled on beamlevel rather than cell level, where one cell can be associated with Nbeams (N can be 1 or >1). Unlike cell, however, beam is a physical layerentity. Therefore, UE mobility management is handled solely on physicallayer. An example of UE mobility scenario based on the second level RRis given in embodiment 1150 of FIG. 11.

After the UE 1111 is associated with the serving cell 1112, the UE 1111is further associated with beam 1151. This is achieved by acquiring abeam or radio resource (RR) acquisition signal from which the UE canacquire a beam identity or identification. An example of beam or RRacquisition signal is a measurement reference signal (RS). Uponacquiring a beam (or RR) acquisition signal, the UE 1111 can report astatus to the network or an associated TRP. Examples of such reportinclude a measured beam power (or measurement RS power) or a set of atleast one recommended “beam identity (ID)” or “RR-ID”. Based on thisreport, the network or the associated TRP can assign a beam (as a radioresource) to the UE 1111 for data and control transmission. When the UE1111 moves to another cell, the boundary between the previous and thenext cells is neither observed nor visible to the UE 1111. Instead ofcell handover, the UE 1111 switches from beam 1151 to beam 1152. Such aseamless mobility is facilitated by the report from UE 711 to thenetwork or associated TRP—especially when the UE 1111 reports a set ofM>1 preferred beam identities by acquiring and measuring M beam (or RR)acquisition signals.

FIG. 12 illustrates an example beam sweeping operation 1200 according toembodiments of the present disclosure. The embodiment of the beamsweeping operation 1200 illustrated in FIG. 12 is for illustration only.FIG. 12 does not limit the scope of this disclosure to any particularimplementation of the beam sweeping operation 1200.

As shown in FIG. 12, the aforementioned initial access procedure 1210and the aforementioned mobility or radio resource management 1220 fromthe perspective of a UE are described. The initial access procedure 1210includes cell ID acquisition from DL synchronization signal(s) 1211 aswell as retrieval of broadcast information (along with systeminformation required by the UE to establish DL and UL connections)followed by UL synchronization (which can include random accessprocedure) 1212. Once the UE completes the UL synchronization, the UE isconnected to the network and associated with a cell. Following thecompletion of initial access procedure, the UE, possibly mobile, is inan RRM state described in 1220. This state includes, first, anacquisition stage 1221 where the UE can periodically (repeatedly)attempt to acquire a “beam” or RR ID from a “beam” or RR acquisitionsignal (such as a measurement RS).

The UE can be configured with a list of beam/RR IDs to monitor. Thislist of “beam”/RR IDs can be updated or reconfigured by the TRP/network.This configuration can be signaled via higher-layer (such as RRC)signaling or a dedicated L1 or L2 control channel. Based on this list,the UE can monitor and measure a signal associated with each of thesebeam/RR IDs. This signal can correspond to a measurement RS resourcesuch as that analogous to CSI-RS resource in LTE system. In this case,the UE can be configured with a set of K>1 CSI-RS resources to monitor.Several options are possible for measurement report 1222. First, the UEcan measure each of the K CSI-RS resources, calculate a corresponding RSpower (similar to RSRP or RSRQ in LTE system), and report it to the TRP(or network). Second, the UE can measure each of the K CSI-RS resources,calculate an associated CSI (which can include CQI and potentially otherCSI parameters such as RI and PMI), and report it to the TRP (ornetwork). Based on the report from the UE, the UE is assigned M≥1“beams” or RRs either via a higher-layer (RRC) signaling or an L1/L2control signaling 1223. Therefore the UE is connected to these M“beams”/RRs.

For certain scenarios such as asynchronous networks, the UE can fallback to cell ID based or cell-level mobility management similar to 3GPPLTE system. Therefore, only one of the two levels of radio resourceentity (cell) is applicable. When a two-level (“cell” and “beam”) radioresource entity or management is utilized, synchronization signal(s) canbe designed primarily for initial access into the network. For mmWavesystems where analog beam sweeping (as shown in FIG. 12) or repetitionmay be used for enhancing the coverage of common signals (such assynchronization signal(s) and broadcast channel), synchronizationsignals can be repeated across time (such as across OFDM symbols orslots or subframes). This repetition factor, however, is not necessarilycorrelated to the number of supported “beams” (defined as radio resourceunits, to be differentiated with the analog beams used in beam sweeping)per cell or per TRP. Therefore, beam identification (ID) is not acquiredor detected from synchronization signal(s). Instead, beam ID is carriedby a beam (RR) acquisition signal such as measurement RS. Likewise, beam(RR) acquisition signal does not carry cell ID (hence, cell ID is notdetected from beam or RR acquisition signal).

Therefore, considering the above new challenges in initial accessprocedure and RRM for the new radio access technology (NR), there is aneed for designing synchronization signals (along with their associatedUE procedures) and primary broadcast channel which carries broadcastinformation (e.g., master information block or MIB).

In the present disclosure, numerology refers to a set of signalparameters which can include subframe duration, sub-carrier spacing,cyclic prefix length, transmission bandwidth, or any combination ofthese signal parameters.

In the present disclosure, numerology refers to a set of signalparameters which can include subframe duration, sub-carrier spacing,cyclic prefix length, transmission bandwidth, or any combination ofthese signal parameters.

For LTE, primary and secondary synchronization signals (PSS and SSS,respectively) are used for coarse timing and frequency synchronizationand cell ID acquisition. Since PSS/SSS is transmitted twice per 10 msradio frame and time-domain enumeration is introduced in terms of systemframe number (SFN, included in the MIB), frame timing is detected fromPSS/SSS to avoid the need for increasing the detection burden from PBCH.In addition, cyclic prefix (CP) length and, if unknown, duplexing schemecan be detected from PSS/SSS. The PSS is constructed from afrequency-domain ZC sequence of length 63, with the middle elementtruncated to avoid using the d.c. subcarrier. Three roots are selectedfor PSS to represent the three physical layer identities within eachgroup of cells. The SSS sequences are based on the maximum lengthsequences (also known as M-sequences). Each SSS sequence is constructedby interleaving two length-31 BPSK modulated sequences in frequencydomain, where the two source sequences before modulation are differentcyclic shifts of the same M-sequence. The cyclic shift indices areconstructed from the physical cell ID group.

Since PSS/SSS detection can be faulty (due to, for instance,non-idealities in the auto- and cross-correlation properties of PSS/SSSand lack of CRC protection), cell ID hypotheses detected from PSS/SSSmay occasionally be confirmed via PBCH detection. PBCH is primarily usedto signal the master block information (MIB) which consists of DL and ULsystem bandwidth information (3 bits), PHICH information (3 bits), andSFN (8 bits). Adding 10 reserved bits (for other uses such as MTC), theMIB payload amounts to 24 bits. After appended with a 16-bit CRC, arate-1/3 tail-biting convolutional coding, 4× repetition, and QPSKmodulation are applied to the 40-bit codeword. The resulting QPSK symbolstream is transmitted across 4 subframes spread over 4 radio frames.Other than detecting MIB, blind detection of the number of CRS ports isalso needed for PBCH. In LTE, the 8-bit SFN in the PBCH is the mostsignificant bit (MSB) and updated every 40 ms. The 2-bit leastsignificant bit (LSB) of radio frame number is not explicitly indicatedin PBCH payload. The UE relies on the blind detection of 4 possiblephases for the PBCH scrambling code to identify the LSB so that the fourtimes of NR-PBCH transmission can be coherently combined within 40 ms.TABLE 1 shows LTE PSS/SSS/PBCH.

TABLE 1 LTE PSS/SSS/PBCH LTE design PSS/SSS PBCH Function Coarse T/F &cell ID MTB acquisition, acquisition [confirming cell ID acquisition]Parameters Cell ID (504 hypotheses), MIB: system BW (3 bits), includedframe timing (2 hypotheses) PHICH info (3 bits), System frame number(SFN): 8-bit MSB of radio frame number, reserved bits (10 bits). Needfor blind CP size, [TDD vs. FDD] Number of antenna ports detection (1, 2or 4 ports) by checking 3 CRC mask, 2-bit LSB of radio frame numberwithin 40 ms (1, 2, 3, 4). Reliability Low to moderate High (protectedwith 16-bit CRC + 1/48 effective code rate)

The essential system information indicated by LTE eNB over logicalchannel in the BCH or DL SCH. There are two parts in SI static part anddynamic part. Static part is called as MIB and is transmitted using BCHand carried by PBCH once every 40 ms. MIB carries useful informationwhich includes channel bandwidth, PHICH configuration details; transmitpower, no. of antennas and SIB scheduling information transmitted alongwith other information on the DL-SCH. Dynamic part is called as SIB andis mapped on RRC SI messages (SI-1,2,3,4,5,6,7,8,9,10,11) over DL-SCHand transmitted using PDSCH at periodic intervals. SI-1 transmittedevery 80 ms, SI-2 every 160 ms and SI-3 every 320 ms. System InformationBlocks are grouped in SI containers. Each SI is composed of multipleSIBs. Each SI usually may have different transmission frequency and maybe sent in a single sub-frame. SIBs are transmitted using BCCH mapped onDL-SCH which in turn mapped on PDSCH.

However, the NR's carrier frequency as well as bandwidth is different.For NR, the transmission bandwidth containing synchronization signalsand PBCH is supposed to be larger than LTE. Moreover, the conventionalperiodic CRS may not be available as LTE. The NR requires new designs,as well as the corresponding transmission schemes.

The present disclosure focuses on the design of NR broadcast signals andchannels. The system information is very essential and the same isbroadcasted by LTE eNB over logical channel BCCH. This logical channelinformation is further carried over transport channel BCH or carried byDL-SCH.

The present disclosure relates generally to wireless communicationsystems and, more specifically, to the design of NR broadcast signals,along with their associated mapping and procedures. NR main informationsignals, termed the NR-MIB and NR-SIB, sent on NR-PBCH or NR-PDSCH inthe present disclosure.

NR is using higher carrier frequency and has larger bandwidth. Theminimum bandwidth for NR-PSS, NR-SSS, and NR-PBCH is larger than that ofLTE. NR-SSS is used to identify the cell-ID. The repeated NR-SSS isadded to improve the robustness, and also TDM repeated pattern assistbetter carrier frequency offset (CFO) estimation, since the CFO inhigher carrier frequency becomes larger.

FIG. 13 illustrates an example PSS/SSS/PBCH in long-term evolutionsystem 1300 according to embodiments of the present disclosure. Theembodiment of the PSS/SSS/PBCH in long-term evolution system 1300illustrated in FIG. 13 is for illustration only. FIG. 13 does not limitthe scope of this disclosure to any particular implementation.

The NR-SSS is also used as the DM-RS to detect PBCH symbols. Therepeated pattern of NR-SSS also improves the channel estimation for PBCHdetection. The location of NR-SSS could be before NR-PSS or afterNR-PSS, as illustrated in FIG. 13.

FIG. 14A illustrates an example TDM based NR-SSS and NRPBCH-transmission 1410 according to embodiments of the presentdisclosure. The embodiment of the TDM based NR-SSS and NRPBCH-transmission 1410 illustrated in FIG. 14A is for illustration only.FIG. 14A does not limit the scope of this disclosure to any particularimplementation.

FIGS. 14B and 14C illustrate examples IFDM based NR-SSS and NR-PBCHtransmissions 1420 and 1430 according to embodiments of the presentdisclosure. The embodiment of the IFDM based NR-SSS and NR-PBCHtransmissions 1420 and 1430 illustrated in FIGS. 14B and 14C are forillustration only. FIGS. 114B and 14C do not limit the scope of thisdisclosure to any particular implementation.

FIGS. 14D and 14E illustrate examples block IFDM based NR-SSS andNR-PBCH transmissions 1440 and 1450 according to embodiments of thepresent disclosure. The embodiment of the block IFDM based NR-SSS andNR-PBCH transmissions 1440 and 1450 illustrated in FIGS. 14D and 14E arefor illustration only. FIGS. 14D and 14E do not limit the scope of thisdisclosure to any particular implementation.

FIGS. 14F and 14G illustrate examples combination ofNR-PSS/NR-SSS/NR-PBCH transmission 1460 and 1470 according toembodiments of the present disclosure. The embodiment of the combinationof NR-PSS/NR-SSS/NR-PBCH transmission 1460 and 1470 illustrated in FIGS.4F and 14G is for illustration only. FIGS. 14F and 14G do not limit thescope of this disclosure to any particular implementation.

The larger distance between the repeated NR-SSS symbols achieves betterCFO estimation, such as 1403-1408 in FIG. 14A-G.

In LTE, the DM-RS is inserted within the 1^(st) and 2^(nd) PBCH symbol.If the NR-SSS as well as the repeated NR-SSS symbols are before NR-PBCH,the channel estimation is carried out ahead of PBCH reception, whichdoes not need to buffer the 1^(st) PBCH symbol. No or less resourceelements of DM-RS are required. Compared with the DM-RS (e.g.,48/(72*4)=16.7% overhead per radio frame) in LTE, to achieve channelestimation based on NR-SSS can save the overhead and leaving moreinformation bits in NR-PBCH symbols.

In LTE, PBCH could be transmitted over single port or multiple antennaports (e.g., 2 ports and 4 ports). At the UE side, UE performs blinddetection on the number of antenna ports, which could cause unnecessaryPBCH decoding latency and complexity. For NR, it is preferred to use thefixed number of antenna port(s) for NR-PBCH to reduce the PBCH decodinglatency and complexity at the UE side. The NR-SSS has same number ofantenna port(s) as NR-PBCH. Also the NR-SSS is sent on the same antennaport as that of NR-PBCH using the same transmission scheme. For example,NR-SSS and NR-PBCH could be transmitted over 1 antenna port, e.g.,{port0} and both use the same transmission diversity scheme, such ascyclic shift delay (CSD)/cyclic delay diversity (CDD) on multiplextransmit antennas, or precoding cycling across SSS and PBCH symbolswithin each radio frames and change the precoding cycling parametersover multiple radio frames. Another example is that NR-SSS and NR-PBCHcould be transmitted over 2 antenna ports, e.g., {port0, port1} and bothuse the same transmission diversity scheme, such as 2-port SFBC in LTE.

Note that combinations of the mapping and multiplexing schemes in FIG.14A-G are also supported in this disclosure. In the present disclosure,a set of NR-PSS/NR-SSS/NR-PB is defined as a SS block and each SS blockis sent periodically. Examples of such a duration is half of a radioframe (such as 5 ms), one radio frame (such as 10 ms), or a multiple ofradio frames (such as 10N-ms where N is an integer greater than 1). Theblock of complex-valued modulated signals d(0), . . . , d (M_(symb)−1)may be mapped on the PBCH symbols, where the number of NR-PBCH symbolsis M_(symb). In FIG. 14A-G, M_(symb)=2 is illustrated. The block ofcomplex-valued symbols y^((p))(0), . . . , y^((p))(M_(symb)−1) for eachantenna port is transmitted during 4 consecutive radio frames startingin each radio frame fulfilling n_(f) mod 4=0 and may be mapped insequence starting with y(0) to resource elements (k, l) constituting thecore set of PBCH resource elements.

In case of single antenna port, p=0 and (p) can be deleted for sake ofsimplicity. The k is the relative subcarrier index for each PBCH symboland l is the relative symbol index of the radio frame including PBCH.The mapping to resource elements (k,l) not reserved for transmission ofreference signals may be in increasing order of first the index k, thenthe index l in slot 1 in subframe 0 and finally the radio frame number.

An example embodiment in FIG. 14A is that each SS block is composed oftime division multiplexing (TDM)-based NR-PSS/SSS/PBCH. For example, in1401A there are one NR-PSS symbol, one NR-SSS symbol and NR-PBCHsymbols. In 1402A there are two NR-SSS symbols at the two edges of theSS block, used for the demodulation of adjacent (M_(symb)) NR-PBCHsymbols, and one NR-PSS inserted in the middle of (M_(symb)) NR-PBCHsymbols. In 1403A and 1404A one more NR-PSS symbol is inserted before orafter the sub-block of NR-SSS plus NR-PBCH to further improve thetime/frequency synchronization as well as the channel estimation forcoherent detection of NR-SSS. The 1405A or 1406A are to send part of1403F or 1404A as a unit by using short periodicity, e.g., 5 ms.

Another example embodiment is in FIG. 14B is that each SS block iscomposed of interleaved frequency division multiplexing (IFDM)-basedNR-SSS/PBCH and combined with TDMed NR-PSS. For example, in 1401B, thereis one NR-PSS symbol followed by (M_(symb)+1) IFDMed NR-SSS/PBCHsymbols. In each IFDMed NR-SSS/PBCH symbol, the NR-SSS resource elements(REs) are mapped on every (M_(symb)+1) subcarriers so that there are1/(M_(symb)+1) subcarriers per symbol are NR-SSS; and the NR-PBCH REsare mapped on the remaining 1−1/(M_(symb)+1) subcarriers per symbol. Inthe m-th symbol of IFDMed NS-SSS/PBCH, where m=0 . . . M_(symb), theNR-SSS subcarrier index is k=mod[(M_(symb)+1)k′+m, N_(subcarrier)] andthe NR-PBCH subcarrier index is =mod[(M_(symb)+1)k′+m+i,N_(subcarrier)], where k′=0, 1, . . .

$\left( {\frac{N_{subcarrier}}{M_{symb} + 1} - 1} \right),$i=1, . . . M_(symb) and N_(subcarrier) is the total number ofsubcarriers.

In 1402B there are two IFDMed NR-SSS/PBCH symbol sub-block on each sideof NR-PSS. In each IFDMed NR-SSS/PBCH symbol sub-block, there are

$\left( {\frac{M_{symb}}{2} + 1} \right)$IFDMed NR-SSS/PBCH symbols. In each IFDMed NR-SSS/PBCH symbol, theNR-SSS resource elements (REs) are mapped on every

$\left( {\frac{M_{symb}}{2} + 1} \right)$subcarriers so that there are

$1/\left( {\frac{M_{symb}}{2} + 1} \right)$subcarriers per symbol are NR-SSS; and the NR-PBCH REs are mapped on theremaining

$1 - {1/\left( {\frac{M_{symb}}{2} + 1} \right)}$subcarriers per symbol. In the m-th symbol of IFDMed NS-SSS/PBCH, wherem=0 . . .

$\frac{M_{symb}}{2},$the NR-SSS subcarrier index is

$k = {{mod}\left\lbrack {{{\left( {\frac{M_{symb}}{2} + 1} \right)k^{\prime}} + m},N_{subcarrier}} \right\rbrack}$and the NR-PBCH subcarrier index is

${k = {{mod}\left\lbrack {{{\left( {\frac{M_{symb}}{2} + 1} \right)k^{\prime}} + m + i},N_{subcarrier}} \right\rbrack}},$where k′=0, 1, . . .

$\left( {\frac{N_{subcarrier}}{\frac{M_{symb}}{2} + 1} - 1} \right),$i=1, . . .

$\frac{M_{symb}}{2}$and N_(subcarrier) is the total number of subcarriers for PBCH payload.

In 1403B and 1404B one more NR-PSS symbol is inserted before or afterthe sub-block of NR-SSS plus NR-PBCH to further improve thetime/frequency synchronization as well as the channel estimation forcoherent detection of NR-SSS.

The 1405C in FIG. 14C is to further squeeze the IFDMed NR-SSS/PBCHsymbols in 1402B into one symbol by using wider BW than that of NR-PSS.The 1406C or 1407C are to send part of 1405C as a unit by using shorterperiodicity. Similarly, the 1408C and 1409C are to further squeeze theIFDMed NR-SSS/PBCH symbols in 1403B and 1404B into one symbol,respectively, by using wider BW than that of NR-PSS. Notice that the BWfor IFDMed NR-SSS/PBCH symbol can be X times of NR-PSS BW and X can beequal to

$1\text{\textasciitilde}{\left( {\frac{M_{symb}}{2} + 1} \right).}$

Another example embodiment is in FIG. 14D is that each SS block iscomposed of Block-IFDM-based NR-SSS/PBCH and combined with TDMed NR-PSS.For example, in 1401D there are one NR-PSS symbol followed by(M_(symb)+1) Block-IFDMed NR-SSS/PBCH symbols. In each Block-IFDMedNR-SSS/PBCH symbol, the NR-SSS resource elements (REs) are mapped on thecontiguous

$\left( \frac{N_{subcarrier}}{M_{symb} + 1} \right) - {subcarrier}$block so that there are 1/(M_(symb)+1) subcarriers per symbol areNR-SSS; and the NR-PBCH REs are mapped on the remaining 1−1/(M_(symb)+1)subcarriers per symbol. In the m-th symbol of Block-IFDMed NS-SSS/PBCH,where m=0 . . . M_(symb), the NR-SSS subcarrier index is

$k = {{mod}\left\lbrack {{{\left( \frac{N_{subcarrier}}{M_{symb} + 1} \right)m} + k^{\prime}},N_{subcarrier}} \right\rbrack}$and the NR-PBCH subcarrier index is

${k = {{mod}\left\lbrack {{{\left( \frac{N_{subcarrier}}{M_{symb} + 1} \right)\left( {m + i} \right)} + k^{\prime}},N_{subcarrier}} \right\rbrack}},$where k′=0, 1, . . .

$\left( {\frac{N_{subcarrier}}{M_{symb} + 1} - 1} \right),$i=1, . . . M_(symb) and N_(subcarrier) is the total number ofsubcarriers for PBCH payload.

In 1402B there are two IFDMed NR-SSS/PBCH symbol sub-block on each sideof NR-PSS. In each IFDMed NR-SSS/PBCH symbol sub-block, there are

$\left( {\frac{M_{symb}}{2} + 1} \right)$IFDMed NR-SSS/PBCH symbols. In each Block-IFDMed NR-SSS/PBCH symbol, theNR-SSS resource elements (REs) are mapped on the contiguous

$\left( \frac{N_{subcarrier}}{\frac{M_{symb}}{2} + 1} \right) - {subcarrier}$block so that there are

$1/\left( {\frac{M_{symb}}{2} + 1} \right)$subcarriers per symbol are NR-SSS; and the NR-PBCH REs are mapped on theremaining

$1 - {1/\left( {\frac{M_{symb}}{2} + 1} \right)}$subcarriers per symbol. In the m-th symbol of Block-IFDMed NS-SSS/PBCH,where m=0 . . .

$\frac{M_{symb}}{2},$the NR-SSS subcarrier index is

$k = {{mod}\left\lbrack {{{\left( \frac{N_{subcarrier}}{\frac{M_{symb}}{2} + 1} \right)m} + k^{\prime}},N_{subcarrier}} \right\rbrack}$and the NR-PBCH subcarrier index is

${k = {{mod}\left\lbrack {{{\left( \frac{N_{subcarrier}}{\frac{M_{symb}}{2} + 1} \right)\left( {m + i} \right)} + k^{\prime}},N_{subcarrier}} \right\rbrack}},$where k′=0, 1, . . .

$\left( {\frac{N_{subcarrier}}{\frac{M_{symb}}{2} + 1} - 1} \right),$i=1, . . .

$\frac{M_{symb}}{2}$and N subcarrier is the total number of subcarriers for PBCH payload.

In 1403D and 1404D one more NR-PSS symbol is inserted before or afterthe sub-block of NR-SSS plus NR-PBCH to further improve thetime/frequency synchronization as well as the channel estimation forcoherent detection of NR-SSS.

The 1405E in FIG. 14E is to further squeeze the Block-IFDMed NR-SSS/PBCHsymbols in 1402D into one symbol by using wider BW than that of NR-PSS.The 1006 c or 1007 c are to send part of 1405E as a unit by usingshorter periodicity. Similarly, the 1408E and 1409E are to furthersqueeze the Block-IFDMed NR-SSS/PBCH symbols in 1403D and 1404D,respectively, into one symbol by using wider BW than that of NR-PSS.Notice that the BW for Block-IFDMed NR-SSS/PBCH symbol can be X times ofNR-PSS BW and X can be equal to

$1\text{\textasciitilde}{\left( {\frac{M_{symb}}{2} + 1} \right).}$

More illustrated combinations of NR-PSS/SSS/PBCH is given in FIGS. 14Fand 14G. Note that the other combinations of the mapping andmultiplexing schemes in FIGS. 14A-14G are also supported in thisdisclosure.

Embodiment 1 illustrates the NR-PBCH Format 1, which is a simple formatwithout considering beam sweeping and may be used in carrier frequency<6GHz, such as 4 GHz. Similar with LTE, the NR-PBCH indicate partialminimum system information (MIB) and the remaining minimum systeminformation (RMSI), which is similar to the SIB1 and SIB2 in LTE, istransmitted in PDSCH or a newly defined secondary physical broadcastcontrol channel (secondary PBCH).

On example of aspect is that the NR-PBCH includes some configuration forthe RMSI transmission. If the RMSI is carried in PDSCH, theconfiguration for the RMSI transmission in NR-PBCH can be theconfiguration of the PDSCH for RMSI transmission, or the configurationof the control resource set, such as PDCCH, which is used to indicatethe scheduling information of the RMSI transmission in PDSCH. If theRMSI or partial RMSI is carried in the secondary PBCH, the configurationfor the RMSI transmission in NR-PBCH can be the configuration of thesecondary PBCH for RMSI transmission.

Another example of aspect is the DC location. Relative to 1.25 MHz (6RBs) in LTE for PSS/SSS/PBCH, the bandwidth for NR-PSS/SSS/PBCH may beextended larger, e.g., 5 MHz, containing more information bits inNR-PBCH. The DC subcarrier of NR wideband may not be in the middle ofsynchronization bandwidth. If the DC location is configurable, the PBCHinclude the indication of DC offset. The DC offset can be pre-definedfor each frequency raster, implicitly indicated by the carrier frequencyof PSS/SSS/PBCH. Or there can be only limited number of bits in PBCH toindicate the predefined patterns of possible DC offsets.

Yet another example of aspect different from LTE is that there is noconventional pre-defined always-on CRS in NR and instead the gNB or TRPmay configure the measurement RS (MRS) distributed over the DL systembandwidth, where the system bandwidth is indicated in PBCH and largerthan that of NR-PSS/SSS/PBCH. This RS can also be defined asconfigurable common RS, tracking RS (TRS) for time/frequencysynchronization (T-F tracking), reduced CRS, or lite CRS, etc. The TRSis configurable but not user-specific, e.g., gNB-specific, TRP-specific,cell-specific, or sector-specific. Alternatively, this RS can be a partof CSI-RS configuration such as cell-specific CSI-RS or level-1 CSI-RS(non-UE-specific CSI-RS).

According to the UE performance/RF specification (e.g., LTEspecification), the UE modulated carrier frequency may be accurate towithin ±0.1 ppm observed over a period of 0.5 ms compared to the carrierfrequency received from the eNB. For example, in case of 4 GHz carrierfrequency, the frequency offset between the UE's receiver and thereceived DL signal can be in the range of ±400 Hz. The UE receiver hasto perform frequency tracking continuously so that the residualfrequency offset observed in each slot does not exceed the ±400 Hz andthus the SNR of the received DL signal is not significantly degraded.For high speed UEs, the additional frequency offset due to the Dopplershift further exacerbate the SNR degradation.

For example, for a UE speed of 100 km/h and carrier frequency of 4 GHz,the resulting Doppler frequency offset is in the range of ±741 Hz. Ifthe UE does not continuously keep tracking of the frequency offset andaccordingly correct the frequency error, the frequency tracking can gooff the convergence range. Although rigorous evaluation may benecessary, estimating and correcting the frequency offset every 5 ms oreven 10 ms, 80 ms based on PSS/SSS does not seem sufficient enoughconsidering LTE system requirement and the Doppler effect. Therefore,the long transmission interval of SS periodicity seems insufficient toprovide reliable frequency tracking.

For time tracking, the bandwidth of the timing measurement signaldetermines the achievable time resolution in time tracking because thetime resolution is inversely proportional to the signal bandwidth. Forexample, comparing the NR-PSS/SSS sent on the 5 MHz bandwidth and thewideband TRS over the whole DL transmission bandwidth of 100 MHz, theachievable time resolution by wideband TRS is roughly 20 times higherthan that of PSS/SSS. Also if we consider the SS block design withsmaller CP length and symbol length for the sake of low latency, thetime tracking becomes more important for both sub6 GHz and over 6 GHz inNR to keep the time synchronization error within the range of CP length.

One example is that the multiple non-co-located transmission points(TRP) sharing the same cell ID. They are synchronized butquasi-colocated (QCL). The TRPs send same PSS/SSS/PBCH using the sharedcell ID. The network can configure one or several antenna ports per TRP.The UE close to one of the TRP could use the TRS on the correspondingantenna port(s) for fine time/frequency/phase tracking. Therefore, TRS(Tracking RS) is necessary especially when we consider the larger SSperiodicity in NR and still try to achieve low latency of thesynchronization before DL signal detection. The TRS configuration mayinclude e.g., the number of antenna ports, periodicity, timing offset,etc.

Although the SIBs signals may be transmitted with low MCS, the SINRrequirement as low as −6 dB is still challenging to get finetime/frequency synchronization with short latency considering the worstcase of the cell-edge users. And it is more efficient to use thesparsely distributed TRS REs instead of the subband dense DM-RS forcontrol channel set. But in some special cases, the TRS is configurableto be switched off. Another example is to turn off the TRS if the cellhas a small coverage without need to consider the high-mobility users.

The NR-PBCH can indicate the TRS configuration, which may include theTRS on/off, number of the antenna port(s), RE pattern, periodicity,resource configuration (time offset, frequency offset), frequencydensity, time density, tx power, etc. For sake of simplicity, the TRSon/off, TRS configuration for NR may reuse some existing configurationsof CSI-RS in LTE. Considering the channel delay spread varies as thecarrier frequency and/or the beamforming precoding, the coherentbandwidth and frequency-selective fading is different. Also the largersubcarrier spacing for higher carrier frequency becomes larger to berobust against the CFO. Therefore, the TRS configuration parametersshould include the configurable frequency density of the TRS REs, orpredefined density adaptive to carrier frequency band, or predefineddensity adaptive to subcarrier spacing of the NR-PBCH or the NR-PDSCH inthe configured bandwidth, or even the combination of the configurablefrequency density but different sets of values for different carrierfrequency and/or different SCS. The frequency density could beimplicitly indicated by antenna port, or the RE pattern index withpredefined RE pattern with different frequency density.

On the other hand, the high mobility is considered for lower frequencyband, such as 120 km/h or even 500 km/h in gNB with large coverage. Thetime-domain channel variation requires more TRS REs in time domain.Therefore, the TRS configuration parameters should include theconfigurable time density of the TRS REs, or predefined density adaptiveto cell coverage/deployment, or predefined density adaptive to carrierfrequency band, or predefined density adaptive to subcarrier spacing ofthe NR-PBCH or the NR-PDSCH in the configured bandwidth, or even thecombination of the configurable frequency density but different sets ofvalues for different cell coverage/deployment, and/or carrier frequency,and/or different SCS. The time density could be implicitly indicated byrepetition time, or the RE pattern index with predefined RE pattern withdifferent time density. In order to reduce the indication bits, anexample is illustrated to define the TRS configuration index to indicateone of the pre-defined patterns of the combination of the configurableparameters as shown in TABLE 2.

TABLE 2 TRS configuration TRS configuration index Parameters of TRSconfiguration 0 TRS off 1 TRS on, 1-port, periodicity1, subframe offsetindex1, RB index1, RE index1 2 TRS on, 2-port, periodicity2, subframeoffset index2, RB index2, RE index2 3 TRS on, 4-port, periodicity3,subframe offset index1, RB index3, RE index3 4 TRS on, 8-port,periodicity4, subframe offset index1, RB index4, RE index4 . . . . . .

In order to reduce the signaling overhead in PBCH, some of theparameters or combinations can be implicitly indicated or fixed. As anillustration, the subframe offset and/or resource block (RB) index maybe same for different antenna port(s), which is sparsely distributedover the indicated BW or one or more subbands in the indicated BW. Theresource element RE index can be aligned with a predefined pattern inthe indicated RB. Some of the resource configurations can also beimplicitly indicated by the cell ID or partial cell ID, which isobtained by detecting SSS, PSS or PSS/SSS. Some examples of resourceconfiguration which can be implicitly indicated by the cell ID orpartial cell ID (such as cell ID group) are RE indices and/or subframeoffset indices.

The periodicity may also be same or pre-defined if the antenna ports areconfigured for QCL TRPs. Or the periodicity may increase as the numberof antenna ports per TRP/gNR is larger.

In one example of aspect is that the NR-PBCH includes the system framenumber (SFN), which provides the time reference for a periodictransmission or configured transmission resource. But the SFN indicationin NR-PBCH could be different from LTE, which is depending on theNR-PBCH periodicity for coherent combining. If the subcarrier spacing ofNR-PSS/SSS/PBCH is twice of that in LTE, each symbol of PBCH containsmore information bits and the NR-PBCH transmission can be coherentlycombined every 20 ms, which may save the accessing time, especially forcell-edge UE. The times of blind detection are reduced bydifferentiating 2 possible phases for the PBCH scrambling code.Alternatively, it may be simpler to use normal/inverted CRC instead of2-phase PBCH scrambling code for implicitly indicate 2-bit LSB of radioframe number.

In another example of aspect is that the NR-PBCH has some reserved bitsfor not only future extension but also for octet aligned of the totalbits. TABLE 3 shows NR-PBCH format.

TABLE 3 NR-PBCH format NR design NR-PBCH Format I Function MIBacquisition, [confirming cell ID acquisition] Parameters SFN: MSB ofradio frame number included In case of SFN = 7, SFN = (radio framenumber) MOD 8 In case of SFN = 8, SFN = (radio frame number) MOD 4 Incase of SFN = 9, SFN = (radio frame number) MOD 2 In case of SFN = 10,SFN = (radio frame number) Configuration for the RMSI transmissionConfiguration of the PDSCH or the configuration of the control resourceset for the PDSCH in case of RMSI in PDSCH Configuration of the PDSCH orsecondary PBCH in case of RMSI or partial RMSI in PDSCH or secondaryPBCH Tracking RS configuration may include the parameters or anycombination of the parameters) TRS On/off TRS port number TRSperiodicity TRS frequency density (the number of REs/sub-carriers usedfor TRS per RB within an OFDM symbol where TRS is received - theREs/sub-carriers can be adjacent/contiguous or distributed/spaced withinthe RB) TRS time density (the number of OFDM symbols used for TRS withinone slot/subframe - the REs/symbols can be adjacent/contiguous ordistributed/spaced within one slot/subframe) TRS resource configuration(including subframe, time offset, bandwidth, subband, resource blockindex, resource element index, frequency density, time density, pattern,etc.) TRS power (if configurable) DC offset (if configurable) Possiblefrequency locations of NR-SS block(s) within system bandwidth E.g., incase of minBW = 5 MHz and maxBW = 40 MHz in the frequency range below 6GHz, 3 bits are used to indicate 8 possible frequency locations. E.g.,in case of minBW = 10 MHz and maxBW = 40 MHz in the frequency rangebelow 6 GHz, 2 bits are used to indicate 4 possible frequency locations.Other reserved bits Need for blind In case of SFN = 7, 3-bit LSB ofradio frame number within 80 ms (1, 2, detection 3, 4, 5, 6, 7, 8) Incase of SFN = 8, 2-bit LSB of radio frame number within 40 ms (1, 2, 3,4) In case of SFN = 9, 1-bit LSB of radio frame number within 20 ms (1,2) In case of SFN = 10, no blind detection Reliability High (protectedwith 16-bit CRC, very low effective code rate)

In some embodiments, NR-PBCH indicates part of the minimum systeminformation (MIB) and the RMSI is carried in the PDSCH, where the RMSItransmission configuration is to use the control resource set, e.g.,PDCCH, to indicate the scheduling information of the PDSCH. The NR-PBCHindicate UEs where to find the control resource set. After detecting thePDCCH, the UEs can get the RMSI in the scheduled PDSCH. For example, theUEs in LTE search the PDCCH with a special System Information RNTI(SI-RNTI) to get the scheduling information of the PDSCH.

The scheduling information of scheduled PDSCH may change due to thevariable SI payload size due to some optional fields. To avoid theNR-PBCH contents change frequently, the configuration for the controlresource set, such as PDCCH, is included in NR-PBCH instead of that ofscheduled PDSCH. It is more easer for the coherent combining at thereceiver side. The configuration for the control resource set includethe frequency resource configuration, e.g., bandwidth, subband, etc. andtime resource configuration, e.g., periodicity, time offset, number ofsymbols, etc. Different from TABLE 3, NR-PBCH contents in theaforementioned embodiments include the configuration of the controlresource set for the RMSI transmission but do not include TRSconfiguration and/or DC offset configuration, or only partial TRSconfiguration, for example, SFN, configuration of control resource setfor the RMSI transmission: frequency resource configuration for controlresource set; and time resource configuration for control resource set,partial Tracking RS configuration (such as on/off, 1 antenna port,default periodicity, frequency density, time density, time offset),other reserved bits, and CRC.

Besides the scheduling information for the scheduled PDSCH, e.g.,periodicity, time offset, subband location, resource block position,etc., which is used for UEs to find the RMSI (similar to the SIB 1 andSIB2 in LTE), the control resource set may also include TRSconfiguration and DC offset configuration (if configurable), forexample, configuration or partial configuration for RMSI in PDSCH:frequency resource configuration for the scheduled PDSCH; time resourceconfiguration for the scheduled PDSCH; transport block size (TBS), MCS,etc.; and numerology of subcarrier spacing, CP length, etc., remainingTracking RS configuration (such as tx power/power boosting, configurableant port if more than 1, configurable periodicity, QCL mapping ofantenna ports or NR-SS blocks, etc.), and DC offset configuration (ifconfigurable).

In some embodiments, NR-PBCH indicates the part of minimum systeminformation (MIB) and the scheduling information for the RMSI in PDSCH.The UEs directly find the scheduled PDSCH based on the indication inNR-PBCH for RMSI transmission. Different from TABLE 3, NR-PBCH contentsin the aforementioned embodiments include the configuration of the PDSCHfor the RMSI transmission but do not include TRS configuration and/or DCoffset configuration or only partial TRS configuration, for example,SFN, configuration of the PDSCH for the RMSI transmission: frequencyresource configuration for the scheduled PDSCH; time resourceconfiguration for the scheduled PDSCH; transport block size (TBS), MCS,etc. for the scheduled PDSCH; numerology of subcarrier spacing, CPlength, etc. for the scheduled PDSCH, partial Tracking RS configuration(such as on/off, 1 antenna port, default periodicity, frequency density,time density, time offset), other reserved bits, and CRC. In suchembodiments, the configuration parameters of the PDSCH for the RMSItransmission are the scheduling information for UEs to find and detectthe RMSI in there. Therefore, the scheduled PDSCH include RMSI orpartial RMSI, remaining Tracking RS configuration (such as txpower/power boosting, configurable ant port if more than 1, configurableperiodicity, QCL mapping of antenna ports or NR-SS blocks, etc.), and DCoffset configuration (if configurable).

In some embodiments, NR-PBCH indicates the part of the minimum systeminformation (MIB) and the configuration for PDSCH for RMSI. The UEsdirectly find the PDSCH based on the indication in NR-PBCH. Differentfrom TABLE 3, NR-PBCH contents in the aforementioned embodiments includethe configuration of the PDSCH for the RMSI transmission but do notinclude TRS configuration and/or DC offset configuration or only partialTRS configuration, such as SFN, configuration of the PDSCH (or secondaryPBCH) for RMSI transmission: frequency resource configuration for thePDSCH; time resource configuration for the PDSCH; transport block size(TBS), MCS, etc. for the PDSCH; and numerology of subcarrier spacing, CPlength, etc. for the PDSCH, partial Tracking RS configuration (such ason/off, 1 antenna port, default periodicity, frequency density, timedensity, time offset), other reserved bits, and CRC. In suchembodiments, the configuration parameters for secondary PBCH or PDSCHare the scheduling information for UEs to find RSMI in there. Thesecondary PBCH or PDSCH may have similar numerology as PBCH but withdifferent periodicity and/or resource allocation. The secondary physicalbroadcast channel contents include RMSI or partial RMSI, remainingTracking RS configuration (such as tx power/power boosting, configurableant port if more than 1, configurable periodicity, QCL mapping ofantenna ports or NR-SS blocks, etc.), and DC offset configuration (ifconfigurable)

Note that some of the parameters or combinations can be implicitlyindicated or fixed to save the signaling overhead in MIB and/or SIB(s).As an illustration, the time resource configuration for MIB in PBCHand/or SIB(s) of RMSI may be fixed or pre-defined, such as periodicity,time offset, and/or number of symbols. Also note that in the aboveembodiments and sub-embodiments, the Tracking RS configuration and DCoffset configuration (if configurable) can be combined together by usingthe pre-defined pattern. Also note that in the above embodiments andsub-embodiments, the Tracking RS configuration, if not indicated in MIBor RMSI, can be indicated in RRC signals carried in PDSCH.

Another possibility is to explicitly indicate partial SFN and implicitlyindicate the remaining bits of SFN. The implicit scheme include usingdifferent scrambling sequences, and/or rate matching with differentredundant versions (RVs), and/or the different CRC masks for the PBCH ineach SFN within PBCH TTI.

For example, assuming PBCH TTI is 80 ms, the 7-bit MSB of SFN isindicated in PBCH payload. The remaining 3-bit LSB is implicitlyindicated by using scrambling sequences. Alternative one is to prepare along scrambling sequence with same length of 8*(Number of PBCH codedbits per NR-SS block). The 8 segments of the long scrambling sequenceare used to multiplex with the PBCH payload with length of (Number ofPBCH coded bits per NR-SS block), sent at {0, 10, 20, 30, 40, 50, 60, 70ms} within PBCH TTI of 80 ms, respectively. Therefore, each cell has onelong scrambling sequences for PBCH.

Alternative two is to generate 8 short scrambling sequences aregenerated with length of (Number of PBCH coded bits per NR-SS block) andpre-allocated for each PBCH payload in each subframe. Therefore, eachcell has a group of 8 short scrambling sequences. The short scramblingsequences can be generated based on the same cell-specific base sequencebut use different cyclic shifts and/or different cover codes on top ofthe base sequence to keep their orthogonality. The cyclic shifts and/orcover codes are subframe-specific. For sake of simplicity, the covercodes could be orthogonal OCC codes, etc.

Alternative three is to generate a pair of long scrambling sequenceswith length of 4*(Number of PBCH coded bits per NR-SS block). The 4segments of one long scrambling sequence are used to multiplex with thePBCH payload with length of (Number of PBCH coded bits per NR-SS block),sent at {0, 20, 40, 60 ms} within PBCH TTI of 80 ms, respectively. The 4segments of another long scrambling sequence are used to multiplex withthe PBCH payload with length of (Number of PBCH coded bits per NR-SSblock), sent at {10, 30, 50, 70 ms} within PBCH TTI of 80 ms,respectively. Therefore, each cell has a pair of long scramblingsequences for PBCH. The two scrambling sequences can be based on thesame cell-specific base sequence but use different cyclic shifts and/ordifferent cover codes on top of the base sequence to keep theirorthogonality. The cyclic shifts and/or cover codes aresubframe-group-specific. For sake of simplicity, the cover codes couldbe orthogonal OCC codes, etc.

In NR, let's assume we have PBCH payload of 64 bits. After Polar codingand rate matching, we could have 768 bits. With 8 times repetition, the768*8 bits are scrambled by using Alt1 long scrambling sequence withlength of 768*8. The QPSK-modulated 384*8 symbols are segmented into 8RVs with each RV has self-decodable 384 symbols. Each RV can be mappedinto the 384 REs in the 2 NR-PBCH symbols excluding the DMRS REs with1/3 overhead. Each segment of scrambling sequence to identify the 3-bitLSB of SFN.

Alternatively, the 768 bits are directly scrambled by using Alt2 8 shortscrambling sequences with length of 768. In case of Alt2, the 8 shortscrambling sequences is pre-defined to differentiate SFN {0, 10, 20, 30,40, 50, 60, 70 ms} within PBCH TTI of 80 ms. The QPSK-modulated 384symbols have self-decodable 384 symbols, mapped into the 384 REs in the2 NR-PBCH symbols excluding the DMRS REs with 1/3 overhead. Each shortscrambling sequence is to identify the 3-bit LSB of SFN.

Alternatively, with 4 times repetition, the 768*4 bits are scrambled byusing Alt3 a pair of long scrambling sequences with length of 768*4. Incase of Alt3, the pair of long scrambling sequences is pre-defined todifferentiate two groups of SFN {0, 20, 40, 60 ms} and {10, 30, 50, 70ms} within PBCH TTI of 80 ms. The QPSK-modulated 384*4 symbols aresegmented into 4 RVs with each RV has self-decodable 384 symbols. EachRV can be mapped into the 384 REs in the 2 NR-PBCH symbols excluding theDMRS REs with 1/3 overhead. Each segment of scrambling sequence is toidentify the 2-bit LSB of SFN. The remaining 1-bit SFN is differentiatedby a pair of scrambling sequences.

In some embodiments, NR-PBCH Format 2 that is a unified formatconsidering both single/multi-beam synchronizations is considered. Thebeam sweeping is used to send NR PSS/SSS/PBCH and the number of beams isconfigurable. A small number of wide beams may be considered in case ofcarrier frequency<6 GHz; while a large Narrow beams may be used incarrier frequency>6 GHz, such as 30 GHz, to combat with significant pathloss/shadowing and extend the coverage.

FIG. 15 illustrates an example beam transmission 1500 according toembodiments of the present disclosure. The embodiment of the beamtransmission 1500 illustrated in FIG. 15 is for illustration only. FIG.15 does not limit the scope of this disclosure to any particularimplementation.

The beam sweeping for multi-beam NR-PSS/SSS/PBCH is illustrated in FIG.15, where a SS burst set is consisting of multiple contiguous ornon-contiguous SS bursts and each SS burst include a group of contiguousor non-contiguous SS blocks. The SS burst can also be defined as SSgroup and the SS burst set can be defined as SS group set. Each SS blocklocation within a SS burst/group set as well as the SS burst/group andSS burst/group set are pre-defined with the measurement window, e.g., 5ms, for each frequency band. The SS burst set is used to carry out thebeam sweeping over the whole cell coverage. In each SS block, there areNR-PSS/SSS/NR-PBCH, which is sent by gNB/TRP with abeamforming/precoding/antenna weights/spatial filtering. Thesingle-beam, illustrated in FIG. 15, is regarded as a special case ofmulti-beam in FIG. 15, where there is only one SS burst and one SS blockper SS burst so that SS block=SS burst=SS burst set.

FIG. 16 illustrates example essential bit information 1600 according toembodiments of the present disclosure. The embodiment of the essentialbit information 1600 illustrated in FIG. 16 is for illustration only.FIG. 16 does not limit the scope of this disclosure to any particularimplementation.

As shown in FIG. 16, the essential information bits indicated in PBCH isdivided into common information and non-common information. The commoninformation can be coherently combined over configured period of time,such as among the SS blocks in a SS burst and/or multiple SS blocks in aSS burst set; while the non-common information may include specificinformation for a SS-block, such as its specific resource configurationincluding LSB of radio frame index, subframe index, symbol index and theSS-block specific TRS configuration if different. In case of multi-beamNR-SS blocks, the TRS could be configured for the beam-specific orbeam-burst-specific RRM measurement. The examples of the DC offsetconfiguration and/or TRS configuration illustrated in the aforementionedembodiments may also apply to the corresponding configurations common tomultiple SS-blocks.

The coding schemes and resource mapping can be designed separately forcommon and non-common information respectively. The codewords and lengthof CRC may be different. In LTE, tail-bite convolutional coding (TBCC)is used for PBCH. If the number of information bits of common ornon-common is small, the simple coding scheme, e.g., Reed-Muller codes,could be used for fast detection.

Although the common and non-common information is separately coded, theyare both mapped into the PBCH symbols with or without symbol boundary.The common information with fixed number of bits is decoded first. Thenumber of remaining bits may be configurable according to the commoninformation. According to the indication in common information, UE mayknow the length of information bits of the following non-common part. Ifthere is no non-common information, the UE may skip the following bitsdetection within the PBCH symbol. Accordingly, the number of PBCHs isconfigurable based on the common information indication.

The NR-PBCH contents in the aforementioned embodiments are illustratedin TABLE 4. Note that the payload size for common and uncommoninformation and/or the number of REs in PBCH to be mapped to carrycommon and uncommon information can be different for different carrierfrequency ranges. For example, the number bits and/or the number of REsto transmit uncommon information for carrier frequency range 0 to 6 GHzcan be smaller than the ones for carrier frequency range 6 to 60 GHz.

TABLE 4 NR-PBCH format 2 NR design NR-PBCH Format 2 Function MIBacquisition, [confirming cell ID acquisition] Parameters Commoninformation may include included SFN In case of SFN = 7, SFN = (radioframe number) MOD 8 In case of SFN = 8, SFN = (radio frame number) MOD 4In case of SFN = 9, SFN = (radio frame number) MOD 2 In case of SFN =10, SFN = (radio frame number) Configuration for the RMSI transmissionConfiguration of the PDSCH or the configuration of the control resourceset for the PDSCH in case of RMSI in PDSCH Configuration of thesecondary PBCH or PDSCH in case of RMSI or partial RMSI in secondaryPBCH or PDSCH Tracking RS common configuration may include theparameters or any combination of the parameters TRS On/off TRS portnumber TRS periodicity TRS frequency density (the number ofREs/sub-carriers used for TRS per RB within an OFDM symbol where TRS isreceived - the REs/sub-carriers can be adjacent/contiguous ordistributed/spaced within the KB) TRS time density (the number of OFDMsymbols used for TRS within one slot/subframe - the REs/symbols can beadjacent/contiguous or distributed/spaced within one slot/subframe) TRSresource configuration (including subframe, resource block index,subband, resource element index, frequency density, time density,pattern, etc.) TRS power (if configurable) DC offset (if configurable)Possible frequency locations of NR-SS block(s) within system bandwidthE.g., in case of minBW = 5 MHz and maxBW = 40 MHz in the frequency rangebelow 6 GHz, 3 bits are used to indicate 8 possible frequency locations.E.g., in case of minBW = 10 MHz and maxBW = 40 MHz in the frequencyrange below 6 GHz, 2 bits are used to indicate 4 possible frequencylocations. E.g., in case of minBW = 50 MHz and maxBW = 400 MHz in thefrequency range from 24 GHz to 52.6 GHz, 3 bits are used to indicate 8possible frequency locations. E.g., in case of minBW = 100 MHz and maxBW= 400 MHz in the frequency range from 24 GHz to 52.6 GHz, 2 bits areused to indicate 4 possible frequency locations. Beam Commonconfiguration for beam sweeping may include Single beam or multi-beamSS-block periodicity SS-block pattern per periodicity: SS burst set,Number of SS bursts per SS burst set, Number of SS blocks per SS burstOther reserved bits Non-common information may include LSB of radioframe number In case of SFN = 7, 3-bit LSB of radio frame number within80 ms (1, 2, 3, 4, 5, 6, 7, 8) In case of SFN = 8, 2-bit LSB of radioframe number within 40 ms (1, 2, 3, 4) In case of SFN = 9, 1-bit LSB ofradio frame number within 20 ms (1, 2) In case of SFN = 10, 0-bit LSBBeam non-common configuration for beam sweeping SS-block index per burstset: localized SS block index within a burst set Or SS-block index perburst: localized SS block index within a burst or the starting symbolindex of each SS-block SS burst index per SS burst set Half frame indexper radio frame (e.g. first or second 5 ms within a radio frame) TRSnon-common configuration (5~10 bits) including TRS resourceconfiguration (if non-common) Need for blind NO detection ReliabilityHigh Common and non-common information are protected by separate CRCwith different low effective code rate

In some embodiments, NR-PBCH indicates part of the minimum systeminformation (MIB) and the RMSI is carried in the PDSCH, where the RMSItransmission configuration is to use the control resource set, e.g.,PDCCH, to indicate the scheduling information of the PDSCH. The NR-PBCHindicate UEs where to find the control resource set. After detecting thePDCCH, the UEs can get the RMSI in the scheduled PDSCH. For example, theUEs in LTE search the PDCCH with a special System Information RNTI(SI-RNTI) to get the scheduling information of the PDSCH.

The scheduling information of scheduled PDSCH may change due to thevariable SI payload size due to some optional fields. To avoid theNR-PBCH contents change frequently, the configuration for the controlresource set, such as PDCCH, is included in NR-PBCH instead of that ofscheduled PDSCH. It is more easer for the coherent combining at thereceiver side. The configuration for the control resource set includethe frequency resource configuration, e.g., bandwidth, subband, etc. andtime resource configuration, e.g., periodicity, time offset, number ofsymbols, etc. Different from TABLE 3, NR-PBCH contents in theaforementioned embodiments include the configuration of the controlresource set for the RMSI transmission but do not include TRSconfiguration and/or DC offset configuration or only partial TRSconfiguration, such as SFN, configuration of control resource set forthe RMSI transmission: frequency resource configuration for controlresource set; and time resource configuration for control resource set,beam Common configuration for beam sweeping, partial Tracking RSconfiguration (such as on/off, 1 antenna port, default periodicity,frequency density, time density, time offset), other reserved bits, andCRC.

Besides the scheduling information for the scheduled PDSCH, e.g.,periodicity, time offset, subband location, resource block position,etc., which is used for UEs to find the RMSI (similar to the SIB 1 andSIB2 in LTE specification), the control resource set may also includeTRS configuration and DC offset configuration (if configurable), such asconfiguration or partial configuration for RMSI in PDSCH: frequencyresource configuration for the scheduled PDSCH; time resourceconfiguration for the scheduled PDSCH; transport block size (TBS), MCS,etc.; and numerology of subcarrier spacing, CP length, etc., remainingTracking RS configuration (such as tx power/power boosting, configurableant port if more than 1, configurable periodicity, QCL mapping ofantenna ports or NR-SS blocks, etc.), and DC offset configuration (ifconfigurable)

In some embodiments, NR-PBCH indicates the part of minimum systeminformation (MIB) and the scheduling information for the RMSI in PDSCH.The UEs directly find the scheduled PDSCH based on the indication inNR-PBCH for RMSI transmission. Different from TABLE 3, NR-PBCH contentsin the aforementioned embodiments include the configuration of the PDSCHfor the RMSI transmission but do not include TRS configuration and/or DCoffset configuration or only partial TRS configuration, such as SFN,configuration of the PDSCH for the RMSI transmission: frequency resourceconfiguration for the scheduled PDSCH; time resource configuration forthe scheduled PDSCH; transport block size (TBS), MCS, etc. for thescheduled PDSCH; and numerology of subcarrier spacing, CP length, etc.for the scheduled PDSCH, beam Common configuration for beam sweeping,partial Tracking RS configuration (such as on/off, 1 antenna port,default periodicity, frequency density, time density, time offset),other reserved bits, and CRC. In such embodiments, the configurationparameters of the PDSCH for the RMSI transmission are the schedulinginformation for UEs to find and detect the RMSI in there. Therefore, thescheduled PDSCH include RMSI or partial RMSI, remaining Tracking RSconfiguration (such as tx power/power boosting, configurable ant port ifmore than 1, configurable periodicity, QCL mapping of antenna ports orNR-SS blocks, etc.), and DC offset configuration (if configurable).

In some embodiments, NR-PBCH indicates the part of the minimum systeminformation (MIB) and the configuration for PDSCH for RMSI. The UEsdirectly find the PDSCH based on the indication in NR-PBCH. Differentfrom TABLE 3, NR-PBCH contents in the aforementioned embodiments includethe configuration of the PDSCH for the RMSI transmission but do notinclude TRS configuration and/or DC offset configuration or only partialTRS configuration, such as SFN, configuration of the PDSCH or (secondaryPBCH) for RMSI transmission: frequency resource configuration for thePDSCH; time resource configuration for the PDSCH; transport block size(TBS), MCS, etc. for the PDSCH; and numerology of subcarrier spacing, CPlength, etc. for the PDSCH, beam Common configuration for beam sweeping,partial Tracking RS configuration (such as on/off, 1 antenna port,default periodicity, frequency density, time density, time offset),other reserved bits, and CRC. In such embodiments, the configurationparameters for secondary PBCH or PDSCH are the scheduling informationfor UEs to find RSMI in there. The secondary PBCH or PDSCH may havesimilar numerology as PBCH but with different periodicity and/orresource allocation. The secondary physical broadcast channel contentsinclude RMSI or partial RMSI, remaining Tracking RS configuration (suchas tx power/power boosting, configurable ant port if more than 1,configurable periodicity, QCL mapping of antenna ports or NR-SS blocks,etc.), and DC offset configuration (if configurable).

Note that some of the parameters or combinations can be implicitlyindicated or fixed to save the signaling overhead in MIB and/or SIB(s).As an illustration, the time resource configuration for MIB in PBCHand/or SIB(s) of RMSI may be fixed or pre-defined, such as periodicity,time offset, and/or number of symbols. Also note that in the aboveembodiments and sub-embodiments, the Tracking RS configuration and DCoffset configuration (if configurable) can be combined together by usingthe pre-defined pattern. Also note that in the above embodiments andsub-embodiments, the Tracking RS configuration, if not indicated in MIBor RMSI, can be indicated in RRC signals carried in PDSCH.

Regarding the configuration of SS blocks, a sub-embodiment is tosemi-statically indicate the UE-specific configuration of the actualtransmission of the SS blocks in a SS burst set by RRC signaling, wherethe configuration of actually transmitted NR-SS blocks may contain thestart/end of the NR-SS block indices for UE monitoring, or multiple setsof the start/end of the NR-SS block indices for UE monitoring, or thestart of NR-SS block index plus the duration and/or the number of theNR-SS blocks for UE monitoring, or sets of the start of NR-SS blockindex plus the duration and/or the number of the NR-SS blocks for UEmonitoring. For example, for above 6 GHz, there are max 64 NR-SS blocksso that the gNB can indicate at most 6-bit start index of the NR-SSblock and at most 6-bit end index of the NR-SS block. In case that someNR-SS block is switched off during the indicated window(s) for UEmonitoring (e.g. the window(s) can be the NR-SS blocks between the startand end block indices), bits in DCI can be used for indication if theUE's PDSCH is scheduled to be multiplexed with the NR-SS block symbols(for example, 1 or 2 bits DCI). With such information, the users can dorate matching of PDSCH if NR-SS block(s) are overlapped with allocatedPDSCH resources and/or make use of remaining slots/symbols to detectcontrol/data signals in the DL subframe including DL NR-SS block(s).

Another sub-embodiment is to semi-statically indicate part of theUE-specific configuration of the actual transmission of the SS blocks ina SS burst set by RRC signaling. The NR-SS blocks transmission may havestrong RSRP (e.g. RSRP is larger than a threshold, where the thresholdcan be either fixed, predefined, or configurable), then the ratematching is carried out for the PDSCH transmission when the allocatedresources for PDSCH is overlapped or partially overlapped with SSblock(s).

Another sub-embodiment is to dynamically indicate the UE-specificconfiguration of the actual transmission of the SS blocks in a SS burstset or part of the configuration in PDCCH. For example, 1 bit or morethan 1 bits in DCI to indicate whether the one or several SS block(s)are present or absent in the allocated resources of a UE's PDSCH. If thecorresponding bit is set as “1,” the UE may carry out the rate matchingon the symbol(s) which there are PSS, SSS, and/or PBCH to receive thePDSCH when SS block resources are overlapped or partially overlappedwith PDSCH bandwidth. If the corresponding bit is set as “0,” the UEdoes not need to carry out the rate matching on the symbol(s) to receivethe PDSCH since the SS block resources are not overlapped with PDSCHbandwidth.

Another sub-embodiment is that the actually transmitted(active/de-active) NR-SS block configuration is transparent to UE. Thescheduling can try to avoid the rate matching of the PDSCH bynon-overlapping or partially overlapping with the NR-SS blocks.

Another possibility is to explicitly indicate partial SFN and implicitlyindicate the remaining bits of SFN. The implicit scheme include usingdifferent scrambling sequences, and/or rate matching with differentredundant versions (RVs), and/or the different CRC masks for the PBCH ineach SFN within PBCH TTI. For example, assuming PBCH TTI is 80 ms, the7-bit MSB of SFN is indicated in PBCH payload. The remaining 3-bit LSBis implicitly indicated by using scrambling sequences.

Alternative one is to prepare a long scrambling sequence with samelength of 8*(Number of PBCH coded bits per NR-SS block). The 8 segmentsof the long scrambling sequence are used to multiplex with the PBCHpayload with length of (Number of PBCH coded bits per NR-SS block), sentat {0, 10, 20, 30, 40, 50, 60, 70 ms} within PBCH TTI of 80 ms,respectively. Therefore, each cell has one long scrambling sequences forPBCH.

Alternative two is to generate 8 short scrambling sequences aregenerated with length of (Number of PBCH coded bits per NR-SS block) andpre-allocated for each PBCH payload in each subframe. Therefore, eachcell has a group of 8 short scrambling sequences. The short scramblingsequences can be generated based on the same cell-specific base sequencebut use different cyclic shifts and/or different cover codes on top ofthe base sequence to keep their orthogonality. The cyclic shifts and/orcover codes are subframe-specific. For sake of simplicity, the covercodes could be orthogonal OCC codes, etc.

Alternative three is to generate a pair of long scrambling sequenceswith length of 4*(Number of PBCH coded bits per NR-SS block). The 4segments of one long scrambling sequence are used to multiplex with thePBCH payload with length of (Number of PBCH coded bits per NR-SS block),sent at {0, 20, 40, 60 ms} within PBCH TTI of 80 ms, respectively. The 4segments of another long scrambling sequence are used to multiplex withthe PBCH payload with length of (number of PBCH coded bits per NR-SSblock), sent at {10, 30, 50, 70 ms} within PBCH TTI of 80 ms,respectively. Therefore, each cell has a pair of long scramblingsequences for PBCH. The two scrambling sequences can be based on thesame cell-specific base sequence but use different cyclic shifts and/ordifferent cover codes on top of the base sequence to keep theirorthogonality. The cyclic shifts and/or cover codes aresubframe-group-specific. For sake of simplicity, the cover codes couldbe orthogonal OCC codes, etc.

In NR, let's assume we have PBCH payload of 64 bits. After Polar codingand rate matching, we could have 768 bits. With 8 times repetition, the768*8 bits are scrambled by using Alt1 long scrambling sequence withlength of 768*8. The QPSK-modulated 384*8 symbols are segmented into 8RVs with each RV has self-decodable 384 symbols. Each RV can be mappedinto the 384 REs in the 2 NR-PBCH symbols excluding the DMRS REs with1/3 overhead. Each segment of scrambling sequences to identify the 3-bitLSB of SFN.

Alternatively, the 768 bits are directly scrambled by using Alt2 8 shortscrambling sequences with length of 768. In case of Alt2, the 8 shortscrambling sequences is pre-defined to differentiate SFN {0, 10, 20, 30,40, 50, 60, 70 ms} within PBCH TTI of 80 ms. The QPSK-modulated 384symbols have self-decodable 384 symbols, mapped into the 384 REs in the2 NR-PBCH symbols excluding the DMRS REs with 1/3 overhead. Each shortscrambling sequence is to identify the 3-bit LSB of SFN.

Alternatively, with 4 times repetition, the 768*4 bits are scrambled byusing Alt3 a pair of long scrambling sequences with length of 768*4. Incase of Alt3, the pair of long scrambling sequences is pre-defined todifferentiate two groups of SFN {0, 20, 40, 60 ms} and {10, 30, 50, 70ms} within PBCH TTI of 80 ms. The QPSK-modulated 384*4 symbols aresegmented into 4 RVs with each RV has self-decodable 384 symbols. EachRV can be mapped into the 384 REs in the 2 NR-PBCH symbols excluding theDMRS REs with 1/3 overhead. Each segment of scrambling sequence is toidentify the 2-bit LSB of SFN. The remaining 1-bit SFN is differentiatedby a pair of scrambling sequences.

FIG. 17 illustrates a flow chart of a method for NR-PBCH construction1700 according to embodiments of the present disclosure. The embodimentof the method for NR-PBCH construction 1700 illustrated in FIG. 17 isfor illustration only. FIG. 17 does not limit the scope of thisdisclosure to any particular implementation.

General steps for construction of NR-PBCH are shown in FIG. 17. Notethat modules or part of the functionalities within the modules in theflow chart can be set as default values such that they do not have anyimpact.

The payload of NR-PBCH contents α₀ ^((i)), . . . , α_(A(i)-1) ^((i))1701 as shown in FIG. 17 can be divided into at most two parts. In oneembodiment, the NR-PBCH contents only have common information, then i=1and A(1) is the size of all common bits. In another embodiment, theNR-PBCH contents have both common and non-common information, then i=1,2and A(i) is the size of common bits and non-common bits correspondingly.Note that A(1) and A(2) may not be the same. Also note that A(1) (e.g.A(1) represents for the common information bits) can be different fordifferent carrier frequency range, and A (2) (e.g. A(2) represents forthe uncommon information bits) can be different for different carrierfrequency range. For example, the value of A(2) for carrier frequencyrange 0 to 6 GHz can be smaller than the value of A(2) for carrierfrequency range 6 to 60 GHz.

In CRC attachment module at step 1702, the entire transport block(s) areused to calculate the CRC parity bits, and the generated parity bits aredenoted as p₀ ^((i)), . . . , (p)_(L(i)-1) ^((i))·L^((i)) is the lengthof parity check bits, or equivalently the length of CRC, for eachcodeword. If there are multiple codewords to be encoded (i>1), the valueL(i) can be the same or different for each codeword. For instance, L(i)can equal to 0 (no CRC attachment), or 4, or 8, or 16, or 24, and chosenindependently for each codeword. For one example, L(1)=8 and L(2)=0.

FIG. 18 illustrates an example frame structure 1800 according toembodiments of the present disclosure. The embodiment of the framestructure 1800 illustrated in FIG. 18 is for illustration only. FIG. 18does not limit the scope of this disclosure to any particularimplementation.

As illustrated in FIG. 18, in one embodiment, the common information ofPBCH may use longer CRC 1801 for error detection (e.g., 16-bit CRC sameas that in LTE); while the non-common information of PBCH with lessnumber of bits may use short CRC 1802 (e.g., 4-bit CRC). In anotherembodiment, only one CRC 1803 is used to protect common information butno CRC is applied to non-common information. In another embodiment, ashort CRC 1804 (note that can be 0-bit CRC, which is effective as noCRC) is generated by common information and a long CRC 1805 is jointlygenerated by common and non-common information. A special case is to userepeated non-common information as its own CRC as illustrated in 1807,where the receiver may further improve the robustness of shortnon-common information based on soft-combining for each radio frame oreach SS-block. The motivation of using separate codewords for common andnon-common information of PBCH is to enable flexible reception withcoherent combining of multiple SS-blocks or multiple radio frames andfast identification of PBCH per SS-block or per radio frame with lesscomplexity of user blind detection.

After the generation of CRC bits, a CRC mask x₀ ^((i)), . . . ,x_(L(i)-1) ^((i)) can be utilized to scramble the CRC sequence accordingto the gNB transmit antenna configuration. The output from scrambling isgiven by c₀ ^((i)), . . . , c_(K(i)-1) ^((i)) 1703 as shown in FIG. 17,where c_(k) ^((i))=α_(k) ^((i)) for k=0, A(i)−1, and c_(k)=(p_(k-A(i))^((i))+x_(k-A(i)) ^((i))) mod 2 for k=A(i), . . . , A(i)+L(i)−1. Notethat by choosing x_(i) ^((i))=0 for all 0≤l≤L(i)−1, the scramblingprocedure has no impact to the CRC bits. In one embodiment, the choiceof CRC mask can be the same as the one for NR-PBCH for a particularnumber of transmit antenna ports. In another embodiment, there can be noCRC mask sequence utilized if the number of transmit antenna ports forNR-PBCH is predefined/fixed and known to UE.

The information bits input to the channel coding module at step 1704 asshown in FIG. 17 are denoted by c₀ ^((i)), . . . , c_(K(i)-1) ^((i)),where C(i)=A(i)+L(i) denotes the number of information bits to beencoded for codeword i. Channel coding codes can be utilized on theinformation bits to generate the encoded codeword(s) d₀ ^((i)), . . . ,d_(D(i)-1) ^((i)) 1705 as shown in FIG. 17. One or multiple of thechannel coding schemes can be utilized for this module. Note that ifthere are multiple codewords to be encoded (i>1), the channel codingscheme can be the same or different for each codeword. Note that theencoded length D(1) (e.g. D(1) represents for the encoded length ofcommon information bits) can be different for different carrierfrequency range, and D (2) (e.g. D (1) represents for the encoded lengthof uncommon information bits) can be different for different carrierfrequency range.

For example, the value of D (2) for carrier frequency range 0 to 6 GHzcan be smaller than the value of D(2) for carrier frequency range 6 to60 GHz. Also note that if the message bits and encoded length fordifferent carrier frequency are different, channel coding schemes canalso be different for different carrier frequency. In one example,Reed-Muller (RM) codes can be utilized to generate the encoded codeword,where D(i)>C(i) and C(i)/D(i) is the rate of RM codes. In anotherexample, tail biting convolutional codes (TBCC) can be utilized togenerate the encoded codeword, where D(i)=C(i) and three streams ofcodes are output by the rate-1/3 TBCC encoder (encoded codewords can bedenoted as d₀ ^((i,s)), . . . , d_(D(i)-1) ^((i,s)) where s=0,1,2). Inyet another example, low-density parity-check (LDPC) codes can beutilized to generate the encoded codeword, where D(i)>C(i) and C(i)/D(i)is the rate of LDPC codes. In yet another example, polar codes can beutilized to generate the encoded codeword, where D(i)>C(i) and C(i)/D(i)is the rate of polar codes. In yet another example, Turbo codes can beutilized to generate the encoded codeword, where D(i)=C(i) and threestreams of codes are output by the rate-1/3 Turbo encoder (encodedcodewords can be denoted as d₀ ^((i,s)), . . . , d_(D(i)-1) ^((i,s))where s=0,1,2).

The encoded codeword(s) are delivered to the rate matching module (1306in FIG. 13). d₀ ^((i)), . . . , d_(D(i)-1) ^((i)), . . . , or d₀^((i,s)), . . . , d_(D(i)-1) ^((i,s)) are repeated and/or truncated toconstruct a sequence with desired length. Then, interleaving (withoutusing cell ID to generate the interleaving index sequence) is performedif desired to generate the output sequence e₀, . . . , e_(E-1) or e₀^((i)), . . . , e_(E(i)-1) ^((i)) depending on whether multiplecodewords are combined in this module 1707 as shown in FIG. 17. Notethat the interleaving index sequence can be constructed such that noeffect of interleaving is performed (equivalent as no interleaving). Inone embodiment, if multiple codewords are encoded from previous modules,they can be combined and rate matched and interleaved together. Inanother embodiment, if multiple codewords are encoded from previousmodules, they can be rate matched and interleaved separately.

The block of bits e₀, . . . , e_(E-1) or e₀ ^((i)), . . . , e_(E(i)-1)^((i)) (depending on whether multiple codewords are combined in channelcoding module) are scrambled with a cell-specific sequence prior tomodulation 1708 as shown in FIG. 17, resulting in a block of scrambledbits f₀, . . . , f_(F-1) or f₀ ^((i)), . . . , f_(F(i)-1) ^((i))(depending on whether multiple codewords are combined in channel codingmodule).

The block of bits f₀, . . . , f_(F-1) or f₀ ^((i)), . . . , f_(F(i)-1)^((i)) (depending on whether multiple codewords are combined in channelcoding module) are modulated 1710 as shown in FIG. 17, resulting in ablock of complex-valued modulation symbols d(0), . . . , d(M−1) ord^((i))(0), . . . , d^((i))(M(i)−1) depending on whether multiplecodewords are combined in channel coding module 1711 as shown in FIG.17, where M or M(i) is the number of symbols. If multiple codewords arenot combined, they can be modulated separately using the same ordifferent modulation schemes. For one example, the modulation scheme forNR-SSS can be BPSK. For another example, the modulation scheme forNR-SSS can be QPSK. For yet another example, the modulation scheme forNR-SSS can be M-FSK. For still another example, the modulation schemefor NR-SSS can be OOK.

The block of modulation symbols may be mapped to layers and precoded1712 as shown in FIG. 17, resulting in a block of vectors y^((p))(0), .. . , y^((p))(M−1) or y^((i,p)) (0), . . . , y^((i,p)) (M (i)−1), where0≤p≤P−1 and P is the number of ports for NR-SSS transmission 1713 asshown in FIG. 17. If multiple codewords are generated from previousmodules and not combined until this module, they can be combined firstin this module and then be mapped to layers and precoded jointly, or canbe mapped to layers and precoded separately. In one embodiment, thenumber of layer is set to 1 and precoding matric is an identity matrix(equivalent as no layer mapping or precoding, and the input and outputof this module are identical). In another embodiment, the method forlayer mapping and precoding can be according to the method for layermapping and precoding in LTE specification.

In yet another embodiment, if NR-SSS and NR-PBCH are jointly coded, themethod for layer mapping and precoding can be the same as the ones forNR-PBCH. The block of complex-valued symbols y^((p)) (0), . . . ,y^((p)) (M−1) or y^((i,p)) (0), . . . , y^((i,p)) (M (i)−1), for eachantenna port p is mapped to the M resource elements available for NR-SSStransmission 1714 as shown in FIG. 17. If multiple streams of symbolsare generated from the preceding module, they are combined in thismodule before mapping. In one embodiment, the mapping to the resourceelements (j, k) may be in the increasing order of first the index j,then the index k in slot 1 in subframe 0 and finally the radio framenumber. In another embodiment, multiple codewords (e.g. two codewordscarrying common and uncommon information correspondingly) are mappedseparately to consecutive REs in frequency domain (For example, 1901,1902 and 1903, which corresponds to different frequency multiplexinglocations and different multiplexing for different PBCH symbols, asshown in FIG. 19).

FIG. 19 illustrates an example RE for common and uncommon information1900 according to embodiments of the present disclosure. The embodimentof the RE for common and uncommon information 1900 illustrated in FIG.19 is for illustration only. FIG. 19 does not limit the scope of thisdisclosure to any particular implementation.

In yet another embodiment, multiple codewords (e.g. two codewordscarrying common and uncommon information correspondingly) are IFDMedmapped with each other (e.g. each of the codewords is mapped tointerleaved REs in frequency domain) (e.g., 1904 and 1905, whichcorresponds to same and different IFDM pattern for different PBCHsymbols, as shown in FIG. 19). In yet another embodiment, multiplecodewords (e.g. two codewords carrying common and uncommon informationcorrespondingly) are block IFDMed mapped with each other (e.g. each ofthe codewords is mapped to interleaved blocks of REs in frequencydomain) (e.g., 1906 and 1907, which corresponds to same and differentblock IFDM pattern for different PBCH symbols).

Note that FIG. 19 is only for illustration purpose, and the same designcan be generalized to different number of symbols and different numberof REs within a symbol. Also note that if multiple OFDM symbols are usedfor PBCH, the multiplexing method of REs for common and uncommoninformation can be same or different across symbols. In one embodiment,if DMRS is also supported for demodulation of PBCH, REs for uncommoninformation can be IFDM or block IFDM mapped using same or similarpattern as DMRS. For example, if payload of DMRS and REs for uncommoninformation are same, RE for uncommon information is mapped neighboringto RE for DMRS. For another example, if payload of DMRS is higher thanREs for uncommon information, RE for uncommon information is mappedneighboring to every K REs for DMRS (where K is the multiple differenceof payload of DMRS and REs for uncommon information). For yet anotherexample, if payload of DMRS is lower than REs for uncommon information,group of K REs for uncommon information is mapped neighboring to RE forDMRS (where K is the multiple difference of REs for uncommon informationand payload of DMRS).

In case of beam sweeping in the aforementioned embodiments and therelated sub-embodiments, let's assume there are limited number K (withK>1) of SS blocks per SS burst and the limited number M of SS burstsillustrated in FIG. 15. Each SS block comprises N OFDM symbols based onthe default subcarrier spacing and pre-defined N. And the SS block hasthe fixed relative position within a SS burst set. Therefore, the UE maybe able to identify at least OFDM symbol index, slot index in a radioframe and radio frame number from an SS block. The time index/indices ofan SS block from which UE may derive symbol, slot index in a radio frameis/are to be down-selected from the following alternatives.

In one example of Alt. 1, one time index for every SS-block within anSS-burst set, e.g., the SS block indices are {i=1 . . . K*M}. Onesub-embodiment to indicate the SS block indices {i=1 . . . K*M} is toutilize different NR-SSS/NR-PBCH multiplexing patterns. For example, asshown in FIG. 16, if there are the three symbols of IFDMedNR-SSS/NR-PBCH within N-symbol SS block, the three types of multiplexingpatterns as {1601 a, 1601 b and 1601 c} are used to indicate 3 adjacentSS block indices or 3 distributed SS block indices. Another example, ifthere are the one or two symbols of IFDMed NR-SSS/NR-PBCH within theN-symbol SS block, the two types of multiplexing patterns as {1602 a,1602 b}, {1603 a, 1603 b}, or {1604 a, 1604 b} are used to indicate 2adjacent SS block indices or 2 distributed SS block indices.

Another sub-embodiment is to use the K*M scrambling sequences todifferentiate the K*M SS block indices. The scrambling sequences areorthogonal or non-orthogonal but low-correlated sequences, e.g.,Zadoff-Chu sequences, m-sequences, Gold sequences or PN-sequence. At thetransmitter side, a scrambling sequence, defined to identify one SSblock index individually, is used to scramble the NR-PBCH resourceelements; and at the receiver side, only if the UE use the samescrambling sequence to detect the NR-PBCH, it can pass the CRC detectionand therefore the UE can find the corresponding SS block index.

Another sub-embodiment is to use the CRC and inverse CRC todifferentiate the 2 adjacent SS block indices or 2 distributed SS blockindices. Another sub-embodiment is to combine the CRC/inverse CRC,and/or scrambling sequences, and/or the NR-SSS/NR-PBCH multiplexingpatterns to jointly indicate the SS block indices within a burst set.

In one example of Alt. 2, one time index that is specific to eachSS-block within an SS-burst, and an SS burst index that is specific toeach SS burst within an SS-burst set. SS burst index is common across SSblocks in each SS-burst. The following SS burst index and SS block indexper SS burst need to be indicated respectively: the SS burst indices are{m=1 . . . M}; and the SS block indices per SS burst are {k=1 . . . K}.

One sub-embodiment to indicate the SS burst indices {m=1 . . . M} is toutilize the following approaches. Within an SS burst, the SS blockindices {k=1 . . . K} can be indicated in NR-PBCH explicitly or in SSsequence implicitly (e.g., partial PSS/SSS sequences, or separatelydefined sequence).

FIGS. 20A and 20B illustrate examples multiplexing patterns 2010 and2020 according to embodiments of the present disclosure. The embodimentof the multiplexing patterns 2010 and 2020 illustrated in FIGS. 20A and20B are for illustration only. FIGS. 20A and 20B do not limit the scopeof this disclosure to any particular implementation.

One sub-embodiment is to use the M different NR-SSS/NR-PBCH multiplexingpatterns. For example, as shown in FIGS. 20A and 20B, the three symbolsof IFDMed NR-SSS/NR-PBCH and the three types of multiplexing patterns as{2001A, 2001B, and 2001C} are used to indicate M=3 SS burst indices.Another example, for M=2 SS bursts per SS burst set, the one or twosymbols of IFDMed NR-SSS/NR-PBCH and the two types of multiplexingpatterns as {2002A, 2002B}, {2003A, 2003B}, or {2004A, 2004B} are usedto indicate M=2 SS burst indices.

Another sub-embodiment is to use the M scrambling sequences todifferentiate the M SS burst indices. The scrambling sequences areorthogonal or non-orthogonal but low-correlated sequences, e.g.,Zadoff-Chu sequences, m-sequences, Gold sequences or PN-sequences. Atthe transmitter side, a scrambling sequence, defined to identify one SSburst index individually, is used to scramble the NR-PBCH resourceelements; and at the receiver side, only if the UE use the samescrambling sequence to detect the NR-PBCH, it can pass the CRC detectionand therefore the UE can find the corresponding SS burst index.

Another sub-embodiment is to use the CRC and inverse CRC todifferentiate the M=2 SS burst indices. Another sub-embodiment is tocombine the CRC/inverse CRC, and/or scrambling sequences, and/or theNR-SSS/NR-PBCH multiplexing patterns to jointly indicate the SS burstindices.

Alternatively, the SS burst indices {m=1 . . . M} are indicated inNR-PBCH explicitly or in SS sequence implicitly (e.g., partial PSS/SSSsequences, or separately defined sequence). Within an SS burst, the SSblock indices {k=1 . . . K} can be indicated by utilizing the followingapproaches. In one sub-embodiment of the different NR-SSS/NR-PBCHmultiplexing patterns, for example, as shown in FIGS. 20A and 20B, thethree symbols of IFDMed NR-SSS/NR-PBCH and the three types ofmultiplexing patterns as {2001A, 2001B, and 2001C} are used to indicateK=3 SS block indices. Another example, for K=2 SS blocks per SS burst,the one or two symbols of IFDMed NR-SSS/NR-PBCH and the two types ofmultiplexing patterns as {2002A, 2002B}, {2003A,2003B}, or {2004A,2004B} are used to indicate K=2 SS block indices.

Another sub-embodiment is to use the K scrambling sequences todifferentiate the K SS block indices. The scrambling sequences areorthogonal or non-orthogonal but low-correlated sequences, e.g.,Zadoff-Chu sequences, m-sequences, Gold sequences or PN-sequence. At thetransmitter side, a scrambling sequence, defined to identify one SSblock index individually, is used to scramble the NR-PBCH resourceelements; and at the receiver side, only if the UE use the samescrambling sequence to detect the NR-PBCH, it can pass the CRC detectionand therefore the UE can find the corresponding SS block index.

Another sub-embodiment is to use the CRC and inverse CRC todifferentiate the K=2 SS block indices. Another sub-embodiment is tocombine the CRC/inverse CRC, and/or scrambling sequences, and/or theNR-SSS/NR-PBCH multiplexing patterns to jointly indicate the SS blockindices.

Note that if there are multiple combinations of the part of the SS burstindices and/or SS block indices to be indicated, the CRC/inverse CRC,and/or scrambling sequences, and/or the NR-SSS/NR-PBCH multiplexingpatterns can be utilized to indicate part of the combinations, and othersignal(s) and/or channel(s) can be utilized to indicate the remainingcombinations.

This component illustrates the details of polar codes based PBCH coding.Note that the design principles and design aspects for PBCH from allother components can be applied to this component as well, and thefeatures that can only be applicable to polar codes based PBCH codingscheme are discussed in this component.

As described in the above, the information/hypotheses carried by PBCHcan be categorized into common and uncommon parts, and one or twocodewords can be utilized for PBCH to deliver theseinformation/hypotheses. Here, polar codes based coding schemes aredescribed.

FIG. 21 illustrates an example two codewords for PBCH coding 2100according to embodiments of the present disclosure. The embodiment ofthe two codewords for PBCH coding 2100 illustrated in FIG. 21 is forillustration only. FIG. 21 does not limit the scope of this disclosureto any particular implementation.

In one embodiment of Alt 1, two codewords are utilized for PBCH codingas shown in FIG. 21. In one example of Alt 1a, information bits of thefirst codeword are common bits in PBCH MIB payload (2101), and frozenbits of the first codeword include both constant bits (2103, e.g. zeros)and uncommon bits in PBCH MIB payload (2102, or other forms includingthe uncommon bits, e.g. scrambling sequence for constant bits).Information bits of the second codeword are uncommon bits in PBCH MIBpayload (2104), and frozen bits are constants (2105, e.g. zeros).

In another example of Alt 1b, information bits of the first codewordinclude common bits in PBCH MIB payload (2106) and uncommon bits in PBCHMIB payload (2107), and frozen bits of the first codeword are constantbits (1708, e.g. zeros). Information bits of the second codeword areuncommon bits in PBCH MIB payload (2109), and frozen bits are constants(2110, e.g. zeros).

In yet another example of Alt 1c, information bits of the first codewordare common bits in PBCH MIB payload (2111), and frozen bits of the firstcodeword are constant bits (2112, e.g. zeros). Information bits of thesecond codeword are uncommon bits in PBCH MIB payload (2113), and frozenbits are constants (2114, e.g. zeros).

FIG. 22 illustrates an example one codeword for PBCH coding 2200according to embodiments of the present disclosure. The embodiment ofthe one codeword for PBCH coding 2200 illustrated in FIG. 22 is forillustration only. FIG. 22 does not limit the scope of this disclosureto any particular implementation.

In some embodiments of Alt 2, one codeword is utilized for PBCH codingas shown in FIG. 22. In one example of Alt 2a, information bits of thecodeword are common bits in PBCH MIB payload (2201), and frozen bits ofthe first codeword include both constant bits (2203, e.g. zeros) anduncommon bits in PBCH MIB payload (2202, or other forms including theuncommon bits, e.g. scrambling sequence for constant bits).

In another example of Alt 1b, information bits of the first codewordinclude common bits in PBCH MIB payload (2204) and uncommon bits in PBCHMIB payload (2205), and frozen bits of the first codeword are constantbits (2206, e.g. zeros). In one embodiment for Alt 1, the two codewordscan be encoded and rate matched to the same number of REs and mapped totwo PBCH symbols. In another embodiment for Alt 1, the two codewords canbe encoded using the same polar encoder (same generator matrix), butrate matched to different number of REs within the PBCH symbols (e.g.the number of REs for transmitting CW2 is smaller). In yet anotherembodiment for Alt 1, the two codewords can be encoded differently, andrate matched to different number of REs within the PBCH symbols (e.g.the number of REs for transmitting CW2 is smaller). In onesub-embodiment, the channel coding scheme of CW2 can be not using polarcodes (in this case, there is no concept of information bits/set orfrozen bits/set). For example, Reed-Muller codes can be utilized toencode CW2.

Note that FIG. 21 and FIG. 22 only illustrate the allocation of commonand uncommon bits for polar codes before channel coding.

After the UE detects a synchronization signal (SS) and decodes thebroadcasted system information, the UE may transmit a PRACH preamble inuplink based on the PRACH Configuration Index included in SIB2 wouldindicate at which frame and subframe that UE is allowed to transmit aphysical random access channel (PRACH) Preamble as well as the PRACHpreamble type, as defined in the 3GPP LTE specification. Thetransmission and reception point (TRP) replies with a random accessresponse (RAR), and the UE transmits a message 3 in the uplink.

The PRACH occupies 6 PRBs in the frequency domain and spans 1 or 2 or 3subframes in the time domain, depending on the specific preamble format.In the frequency domain, several subcarriers at both ends of the 6 PRBsare not used to avoid interference with the adjacent PUCCH/PUSCH. In thetime domain, the cyclic prefix (CP) and guard time (GT) are used toavoid interference with the previous and next subframes. As it turnsout, the GT determines the maximum cell radius. The Preamble format isdefined in LTE specification.

FIG. 23 illustrates an example PRACH format 2300 according toembodiments of the present disclosure. The embodiment of the PRACHformat 2300 illustrated in FIG. 23 is for illustration only. FIG. 23does not limit the scope of this disclosure to any particularimplementation.

In FDD, preamble format 0-3 is used. In TDD, preamble format 0-4 areused and the usage of preamble format depends on UL/DL configurationused. There might be multiple random access resources in an UL subframedepending on the UL/DL configuration, e.g., preamble format 1 requires 2subframes and format 3 requires 3 subframes, as shown in FIG. 23. Thenumber of available UL subframe depends on UL/DL configuration used. ThePreamble Format 4 (short PRACH) is only used in TD-LTE, which can betransmitted in the UpPTS part of the special subframe (subframe 1 and/orsubframe 6). Minimum number of symbols needed for this is 2. Hence thiscan be applied only for Special sub frame configurations 5-8 with normalCP or configuration 4-6 with extended CP. PRACH configuration indexes 48to 57 may use short PRACH. TABLE 5 shows PRACH configuration parameters.

TABLE 5 PRACH configuration System frame number Subframe number 0 Even 11 Even 4 2 Even 7 3 Any 1 4 Any 4 5 Any 7 6 Any 1, 6 7 Any 2, 7 8 Any 3,8 9 Any 1, 4, 7 10 Any 2, 5, 8 11 Any 3, 6, 9 12 Any 0, 2, 4, 6, 8 13Any 1, 3, 5, 7, 9 14 Any 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 15 Even 9

In LTE, the RACH procedure may be triggered by the following events. Atstep 1, for initial access and non-synchronized UEs, an initial accessafter radio link failure. At step 2, for RRC_IDLE and non-synchronizedUEs, an initial access from RRC_IDLE. At step 3, for RRC_connected andnon-synchronized UEs: handover requiring random access procedure; DLdata arrival during RRC_CONNECTED when UL is “non-synchronised;” UL dataarrival during RRC_CONNECTED when UL is “non-synchronised.” At step 4,for RRC_connected and synchronized UEs: scheduling Request (SR) if thereare no PUCCH resources for SR available; and positioning if UE's TAtimer has expired, and UE needs to send or receive data, it performsrandom access.

The NR may support RA procedure for both RRC_IDLE UEs and RRC_CONNECTEDUEs. Also both contention-based and contention-free RA procedure may besupported. The contention-free procedure is initiated from network incase of a handover. The present disclosure focuses on the design of NRcontention-based RACH procedure for the RRC_CONNECTED synchronized UEs,since in NR there may be a large number of RRC_CONNECTED UEs or devices(e.g., in machine-type communication, MTC) and the limited PUCCHresources are not enough for sending request of uplink data transmissionand additional request of beam refinement or beam management in NR. InLTE, the RRC_CONNECTED synchronized UEs use the same PRACH formats asthat of non-synchronized UEs with long CP and symbol length as well aslarge overhead of guard band and guard time. It is more demanding forthe NR UEs to improve the efficiency of contention-based RACH procedure.

The present disclosure relates generally to wireless communicationsystems and, more specifically, to the design of NR PRACH formats, alongwith their associated NR-PRACH configuration, NR-PRACH preamble andNR-PRACH procedures. The design of PRACH formats and transmissionschemes as well as configuration method are illustrated in the followingembodiments. Herein, a class of methods and apparatuses are disclosed,which may increase the network efficiency by reducing the collisionprobability of random access and decreasing the overhead of PRACHtransmission per UE.

Note that whereas many alterations and modifications of the presentdisclosure may not be doubt become apparent to a person of ordinaryskill in the art after having read the foregoing description, it is tobe understood that any particular embodiment shown and described by wayof illustration is in no way intended to be considered limiting.Therefore, references to details of various embodiments are not intendedto limit the scope of the claims which in themselves recite only thosefeatures regarded as essential to the present disclosure.

FIG. 24 illustrates another example PRACH format 2400 according toembodiments of the present disclosure. The embodiment of the PRACHformat 2400 illustrated in FIG. 24 is for illustration only. FIG. 24does not limit the scope of this disclosure to any particularimplementation.

The PRACH format for the RRC_CONNECTED synchronized UEs can have shorterCP and shorter symbol duration. As illustrated in FIG. 24, the LTE PRACHpreamble format 0 is based on a PRACH preamble sequence of length 24576Ts. This length corresponds to a sub-carrier spacing of 1.25 kHz, incontrast to PUSCH and PUCCH which use a sub-carrier spacing of 15 kHz.For LTE release 8, the inter-carrier interference, due to differentsub-carrier spacing, is limited by having small guard bands betweenPRACH and PUSCH and by allocating PRACH to a single interval of adjacentsub-carriers. Also, the small sub-carrier spacing makes the PRACHpreamble more sensitive to frequency errors and other impairments ascompared to other physical channels. Therefore, if the short PRACHsymbol has same numerology as data symbol in PUSCH as well as thecontrol symbol in PUCCH, no guard band (GB) is needed because of theorthogonality between PRACH and UL data. The PRACH symbol with same CPis timely aligned with the data symbol and the processing in the basestation can be using the same FFT for both the data and the PRACH.Although the numerology may be different depending on the frequencyranges, the system information is used for all UL transmission, i.e.,PRACH, PUSCH, and PUCCH, and no additional system information is neededto differentiate PRACH, at least for RRC_CONNECTED synchronized users.

Within the same length of the long PRACH format 0, there are 14 symbolsin case of normal CP length. For the conventional contention-based RA,the UEs are identified by using the PRACH preamble index only and thetwo UEs may collide if they select the same long preamble in sameindicated PRACH resources. Instead, the short PRACH format allows UEs torandomly select a subset of PRACH resources. The UE can be distinguishedby more than one parameter, e.g., the PRACH preamble index and thesubset PRACH resource index. It may reduce collision probability byusing the short PRACH format. The more number of PRACH resource subsetsachieve larger gain on collision reduction. The short PRACH preamblescan be a sequence with shorter length catered with the number ofsubcarriers within the short symbol, i.e., 72 subcarriers within 6 PRBsof PRACH bandwidth. Instead of sending the long PRACH preamble, theshort length of PRACH preamble costs less power consumption per UEcontention.

As illustrated in FIG. 24, each subset consists of one or several shortsymbols (contiguous or non-contiguous), and the number of symbols isconfigurable and indicated by the system information. The UEs can beconfigured to repeat the short PRACH preamble/symbol in the selectedsubset PRACH resources. Repeated symbols improve the PRACH detectionperformance and the carrier frequency offset estimation at the receiverside. The subset can be non-overlapped (orthogonal) or partiallyoverlapped (non-orthogonal). The non-orthogonal subset configuration mayincrease the total number of subsets at the price of the detectionperformance.

In order to control the signaling overhead of PRACH resource subsetselection, the network can pre-define a pattern or several patterns. Thesystem information block (MIB or SIB) indicate the pattern index withvery limited signal overhead. As shown in FIG. 24, the TDMA patterns areillustrated as: (1) pattern1, select a subset resource consisting of onesymbol as 2401 as shown in FIG. 24; (2) pattern2, select a subsetresource consisting of two consecutive symbols as 2402 as shown in FIG.24; and (3) pattern3, select a subset resource consisting of twodistributed symbols as 2403 as shown in FIG. 24.

In case of Pattern 1 2401 of FIG. 24, each PRACH subset has 72subcarriers and there are 14 orthogonal subsets. The symbol/subsetpositions are another orthogonal dimension to separate users. It haslarger multiplexing capacity than that of the LTE PRACH format 0 withinsame resources of 6 PRBs over 1 ms, which has only 839 subcarriers andonly support 64 orthogonal preambles per cell.

For the sake of larger random access capacity, similar patterns may beextended to longer period of PRACH resources, e.g., to have same cost ofPRCH format 1, 2 in FIG. 23 with 14×2 symbols, or that of PRACH format 3in FIG. 23 with 14×3 symbols.

For special subframe, UpPTS in TDD mode, similar patterns may be cut toshorter period of PRACH resources, e.g., to have same cost of PRACHformat 4 in FIG. 23 with 2 symbols.

FIG. 25 illustrates yet another example PRACH format 2500 according toembodiments of the present disclosure. The embodiment of the PRACHformat 2500 illustrated in FIG. 25 is for illustration only. FIG. 25does not limit the scope of this disclosure to any particularimplementation.

The PRACH format for the RRC_CONNECTED synchronized UEs can have shorterCP and shorter symbol duration. As illustrated in FIG. 25, the LTE PRACHpreamble format 0 is based on a PRACH preamble sequence of length 24576Ts. This length corresponds to a sub-carrier spacing of 1.25 kHz, incontrast to PUSCH and PUCCH which use a sub-carrier spacing of 15 kHz.For LTE release 8, the inter-carrier interference, due to differentsub-carrier spacing, is limited by having small guard bands betweenPRACH and PUSCH and by allocating PRACH to a single interval of adjacentsub-carriers. Also, the small sub-carrier spacing makes the PRACHpreamble more sensitive to frequency errors and other impairments ascompared to other physical channels. Therefore, if the short PRACHsymbol has same numerology as data symbol in PUSCH as well as thecontrol symbol in PUCCH, no guard band (GB) is needed because of theorthogonality between PRACH and UL data. The PRACH symbol with same CPis timely aligned with the data symbol and the processing in the basestation can be using the same FFT for both the data and the PRACH.Although the numerology may be different depending on the frequencyranges, the system information is used for all UL transmission, i.e.,PRACH, PUSCH, and PUCCH, and no additional system information is neededto differentiate PRACH, at least for RRC_CONNECTED synchronized users.

Within the same length of the long PRACH format 0, there are 14 symbolsin case of normal CP length. For the conventional contention-based RA,the UEs are identified by using the PRACH preamble index only and thetwo UEs may collide if they select the same long preamble in sameindicated PRACH resources. Instead, the short PRACH format allows UEs torandomly select a subset of PRACH resources. The UE can be distinguishedby more than one parameter, e.g., the PRACH preamble index and thesubset PRACH resource index. It may reduce collision probability byusing the short PRACH format. The more number of PRACH resource subsetsachieve larger gain on collision reduction. The short PRACH preamblescan be a sequence with shorter length catered with the number ofsubcarriers within the short symbol, i.e., 72 subcarriers within 6 PRBsof PRACH bandwidth. Instead of sending the long PRACH preamble, theshort length of PRACH preamble costs less power consumption per UEcontention.

As illustrated in FIG. 25, each subset consists of multiple contiguousrepeated short symbols scrambled by CDM codes, and the number of symbolsis configurable and indicated by the system information. Note that theCDM codes can be orthogonal codes, such as P-matrix, OVSF codes,DFT-matrix, etc. The subset can be non-overlapped (orthogonal) orpartially overlapped (non-orthogonal). The non-orthogonal subsetconfiguration may increase the total number of subsets at the price ofthe detection performance.

In order to control the signaling overhead of PRACH resource subsetselection, the network can pre-define a pattern or several patterns. Thesystem information block (MIB or SIB) indicate the pattern index withvery limited signal overhead. As shown in FIG. 25, the CDM+TDM patternsare illustrated as: (1) pattern1, select a subset resource consisting of2 consecutive symbols with 2×2 CDM codes as 1101 as shown in FIG. 25;(2) pattern2, select a subset resource consisting of 4 consecutivesymbols with 4×4 CDM codes as 1102 as shown in FIG. 25; and (3)pattern3, select a subset resource consisting of 14 consecutive symbolswith 14×14 CDM codes as 1103 as shown in FIG. 25.

In case of Pattern 1 2501 of FIG. 25, each PRACH subset has 72subcarriers and there are 7 orthogonal subsets with 2 CDM codes. Thesymbol/subset positions as well as CDM codes are additional orthogonaldimension to separate users. It has larger multiplexing capacity thanthat of the LTE PRACH format 0 within same resources of 6 PRBs over 1ms, which has only 839 subcarriers and only support 64 orthogonalpreambles per cell.

For the sake of larger random access capacity, similar patterns may beextended to longer period of PRACH resources, e.g., to have same cost ofPRCH format 1, 2 in FIG. 23 with 14×2 symbols, or that of PRACH format 3in FIG. 23 with 14×3 symbols. For special subframe, UpPTS in TDD mode,similar patterns may be cut to shorter period of PRACH resources, e.g.,to have same cost of PRACH format 4 as shown in FIG. 23 with 2 symbols.

FIG. 26 illustrates yet another example PRACH format 2600 according toembodiments of the present disclosure. The embodiment of the PRACHformat 2600 illustrated in FIG. 26 is for illustration only. FIG. 26does not limit the scope of this disclosure to any particularimplementation.

The PRACH format for the RRC_CONNECTED synchronized UEs can have shorterCP and shorter symbol duration. As illustrated in FIG. 26, the LTE PRACHpreamble format 0 is based on a PRACH preamble sequence of length 24576Ts. This length corresponds to a sub-carrier spacing of 1.25 kHz, incontrast to PUSCH and PUCCH which use a sub-carrier spacing of 15 kHz.For LTE release 8, the inter-carrier interference, due to differentsub-carrier spacing, is limited by having small guard bands betweenPRACH and PUSCH and by allocating PRACH to a single interval of adjacentsub-carriers. Also, the small sub-carrier spacing makes the PRACHpreamble more sensitive to frequency errors and other impairments ascompared to other physical channels. Therefore, if the short PRACHsymbol has same numerology as data symbol in PUSCH as well as thecontrol symbol in PUCCH, no guard band (GB) is needed because of theorthogonality between PRACH and UL data. The PRACH symbol with same CPis timely aligned with the data symbol and the processing in the basestation can be using the same FFT for both the data and the PRACH.Although the numerology may be different depending on the frequencyranges, the system information is used for all UL transmission, i.e.,PRACH, PUSCH, and PUCCH, and no additional system information is neededto differentiate PRACH, at least for RRC_CONNECTED synchronized users.

Within the same length of the long PRACH format 0, there are 14 symbolsin case of normal CP length. For the conventional contention-based RA,the UEs are identified by using the PRACH preamble index only and thetwo UEs may collide if they select the same long preamble in sameindicated PRACH resources. Instead, the short PRACH format allows UEs torandomly select a subset of PRACH resources. The UE can be distinguishedby more than one parameter, e.g., the PRACH preamble index and thesubset PRACH resource index. It may reduce collision probability byusing the short PRACH format. The more number of PRACH resource subsetsachieve larger gain on collision reduction. The short PRACH preamblescan be a sequence with shorter length catered with the number ofsubcarriers within the short symbol, i.e., 72 subcarriers within 6 PRBsof PRACH bandwidth. Instead of sending the long PRACH preamble, theshort length of PRACH preamble costs less power consumption per UEcontention.

As illustrated in FIG. 26, each subset consists of interleaved subbandswith a group of subcarriers per short symbol, and the number ofsubcarrier per subband is configurable and indicated by the systeminformation. The UEs can be configured to repeat the interleavedsubbands in the selected subset PRACH resources. Repeated subbandsimprove the PRACH detection performance and carrier frequency offset(CFO) estimation at the receiver side. The subset can be non-overlapped(orthogonal) or overlapped (non-orthogonal). The non-orthogonal subsetconfiguration may increase the total number of subsets at the price ofthe detection performance.

In order to control the signaling overhead of PRACH resource subsetselection, the network can pre-define a patter or several patterns. Thesystem information block (MIB or SIB) indicate the pattern index withvery limited signal overhead. As shown in FIG. 26, the IFDM patterns areillustrated as: (1) pattern1, select a subset resource consisting ofinterleaved subbands with 5 subcarriers every one symbol as 1301 asshown in FIG. 26; (2) pattern2, select a subset resource consisting ofinterleaved subbands with 10 subcarriers every two consecutive symbolsas 2602 in FIG. 26; and (3) pattern3, select a subset resourceconsisting of interleaved subbands with 10 subcarriers every twodistributed consecutive symbols as 2603 in FIG. 26.

In case of Pattern 1 2601 of FIG. 26, each PRACH subset has 70subcarriers, and 14 subbands are distributed in 14 symbols. Thesubband/subset position is another orthogonal dimension to separateusers. It has larger multiplexing capacity than that of the LTE PRACHformat 0 within same resources of 6 PRBs over 1 ms, which has only 839subcarriers and only support 64 orthogonal preambles per cell. For thesake of larger random access capacity, similar patterns may be appliedto longer period of PRACH resources, e.g., to have same cost of PRCHformat 1, 2 in FIG. 23 with 14×2 symbols, or that of PRACH format 3 inFIG. 23 with 14×3 symbols. For special subframe, UpPTS in TDD mode,similar patterns may be cut to shorter period of PRACH resources, e.g.,to have same cost of PRACH format 4 in FIG. 23 with 2 symbols.

Although the present disclosure has been described with an exemplaryembodiment, various changes and modifications may be suggested to oneskilled in the art. It is intended that the present disclosure encompasssuch changes and modifications as fall within the scope of the appendedclaims.

None of the description in this application should be read as implyingthat any particular element, step, or function is an essential elementthat must be included in the claims scope. The scope of patented subjectmatter is defined only by the claims. Moreover, none of the claims areintended to invoke 35 U.S.C. § 112(f) unless the exact words “means for”are followed by a participle.

What is claimed is:
 1. A base station comprising: a controllerconfigured to: generate a primary synchronization signal (PSS) at afirst orthogonal frequency division multiplexing (OFDM) symbol of asynchronization signal (SS) block based on one antenna port, generate asecondary synchronization signal (SSS) at a second OFDM symbol of the SSblock based on the one antenna port, wherein the first OFDM symbol isperfectly separated with the second OFDM symbol and is located prior tothe second OFDM symbol in the SS block, and generate a physicalbroadcast channel (PBCH) at the second OFDM symbol of the SS block basedon the one antenna port, wherein the PBCH is frequency divisionmultiplexed with the SSS only at the second OFDM symbol of the SS block,wherein a bandwidth of the SSS and the PBCH in the second OFDM symbol isX times larger than a bandwidth of the PSS in the first OFDM symbol, andwherein X has a value that is less than two and greater than one; and atransceiver operably coupled with the controller, the transceiverconfigured to transmit the SS block including the PSS, the SSS, and thePBCH.
 2. The base station of claim 1, wherein the bandwidth for the SSSand the PBCH of the second OFDM symbol of the SS block is larger thanthe bandwidth for all signal(s) in the first OFDM symbol of the SSblock, and wherein the PSS is the only signal in the first OFDM symbolof the SS block.
 3. The base station of claim 1, wherein the PBCH isfrequency division multiplexed with the SSS by a contiguous subcarrierblock level, at the second OFDM symbol of the SS block.
 4. The basestation of claim 1, wherein a number of a SS block and location of theSS block are configured within a half frame.
 5. The base station ofclaim 1, wherein a measurement for radio resource management (RRM) isperformed based on a channel state information reference signal(CSI-RS).
 6. A method by a base station, the method comprising:generating a primary synchronization signal (PSS) at a first orthogonalfrequency division multiplexing (OFDM) symbol of a synchronizationsignal (SS) block based on one antenna port; generating a secondarysynchronization signal (SSS) at a second OFDM symbol of the SS blockbased on the one antenna port, wherein the first OFDM symbol isperfectly separated with the second OFDM symbol and is located prior tothe second OFDM symbol in the SS block; generating a physical broadcastchannel (PBCH) at the second OFDM symbol of the SS block based on theone antenna port, wherein the PBCH is frequency division multiplexedwith the SSS only at the second OFDM symbol of the SS block, wherein abandwidth of the SSS and the PBCH in the second OFDM symbol is X timeslarger than a bandwidth of the PSS in the first OFDM symbol, and whereinX has a value that is less than two and greater than one; andtransmitting the SS block including the PSS, the SSS, and the PBCH. 7.The method of claim 6, wherein the bandwidth for the SSS and the PBCH ofthe second OFDM symbol of the SS block is larger than the bandwidth forall signal(s) in the first OFDM symbol of the SS block, and wherein thePSS is the only signal in the first OFDM symbol of the SS block.
 8. Themethod of claim 6, wherein the PBCH is frequency division multiplexedwith the SSS by a contiguous subcarrier block level, at the second OFDMsymbol of the SS block.
 9. The method of claim 6, wherein a number of aSS block and location of the SS block are configured within a halfframe.
 10. The method of claim 6, wherein a measurement for radioresource management (RRM) is performed based on a channel stateinformation reference signal (CSI-RS).
 11. A terminal comprising: atransceiver; and a controller coupled with the transceiver andconfigured to: identify a primary synchronization signal (PSS) at afirst orthogonal frequency division multiplexing (OFDM) symbol of asynchronization signal (SS) block based on one antenna port, identify asecondary synchronization signal (SSS) at a second OFDM symbol of the SSblock based on the one antenna port, wherein the first OFDM symbol isperfectly separated with the second OFDM symbol and is located prior tothe second OFDM symbol in the SS block, and identify a physicalbroadcast channel (PBCH) at the second OFDM symbol of the SS block basedon the one antenna port, wherein the PBCH is frequency divisionmultiplexed with the SSS only at the second OFDM symbol of the SS block,wherein a bandwidth of the SSS and the PBCH in the second OFDM symbol isX times larger than a bandwidth of the PSS in the first OFDM symbol, andwherein X has a value that is less than two and greater than one. 12.The terminal of claim 11, wherein the bandwidth for the SSS and the PBCHof the second OFDM symbol of the SS block is larger than the bandwidthfor all signal(s) in the first OFDM symbol of the SS block, and whereinthe PSS is the only signal in the first OFDM symbol of the SS block. 13.The terminal of claim 11, wherein the PBCH is frequency divisionmultiplexed with the SSS by a contiguous subcarrier block level, at thesecond OFDM symbol of the SS block.
 14. The terminal of claim 11,wherein a number of a SS block and location of the SS block areconfigured within a half frame.
 15. The terminal of claim 11, wherein ameasurement for radio resource management (RRM) is performed based on achannel state information-reference signal (CSI-RS).
 16. A method by aterminal, the method comprising: identifying a primary synchronizationsignal (PSS) at a first orthogonal frequency division multiplexing(OFDM) symbol of a synchronization signal (SS) block based on oneantenna port; identifying a secondary synchronization signal (SSS) at asecond OFDM symbol of the SS block based on the one antenna port,wherein the first OFDM symbol is perfectly separated with the secondOFDM symbol and is located prior to the second OFDM symbol in the SSblock; and identifying a physical broadcast channel (PBCH) at the secondOFDM symbol of the SS block based on the one antenna port, wherein thePBCH is frequency division multiplexed with the SSS only at the secondOFDM symbol of the SS block, wherein a bandwidth of the SSS and the PBCHin the second OFDM symbol is X times larger than a bandwidth of the PSSin the first OFDM symbol, and wherein X has a value that is less thantwo and greater than one.
 17. The method of claim 16, wherein thebandwidth for the SSS and the PBCH of the second OFDM symbol of the SSblock is larger than the bandwidth for all signal(s) in the first OFDMsymbol of the SS block, and wherein the PSS is the only signal in thefirst OFDM symbol of the SS block.
 18. The method of claim 16, whereinthe PBCH is frequency division multiplexed with the SSS by a contiguoussubcarrier block level, at the second OFDM symbol of the SS block. 19.The method of claim 16, wherein a number of a SS block and location ofthe SS block are configured within a half frame.
 20. The method of claim16, wherein a measurement for radio resource management (RRM) isperformed based on a channel state information-reference signal(CSI-RS).